15.1.2 Exam: Semester Exam
ŽA
This graph shows the energy of a reaction over time. Which statement is
true?
Potential energy
N
Reaction progress
O A. G represents the activation energy
OB. H represents the energy of the products,
O C. G represents the energy of the products.
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Answer:

Explanation:

Answer:

The impact force is 98000 N.

Explanation:

mass = 10 tons

The impact force is the weight of the object.

Weight =mass x gravity

W = 10 x 1000 x 9.8

W = 98000 N

The impact force is 98000 N.

Explanation:

The area of a circle of radius r is given by

[tex]A = \pi r^2[/tex]

Taking the derivative of A with respect to time t, we get

[tex]\dfrac{dA}{dt} = 2\pi r \dfrac{dr}{dt}[/tex]

We also know that

[tex]\dfrac{dr}{dt} = 2\:\text{m/s}\:\text{at}\:r = 39\:\text{m}[/tex]

[tex]\dfrac{dA}{dt} = 2\pi (39\:\text{m})(2\:\text{m/s})= 490\:\text{m}^2\text{/s}[/tex]

Answer:

Acosθ

Explanation:

The x-component of a vector is defined as :

Magnitude * cosine of the angle

Maginitude * cosθ

The magnitude is represented as A

Hence, horizontal, x - component of the vector is :

Acosθ

Furthermore,

The y-component is taken as the sin of the of the angle multiplied by the magnitude

Vertical, y component : Asinθ

Answer:

[tex]I_2=30.9A[/tex]

Explanation:

From the question we are told that:

Wire segment [tex]l_s=2.9m[/tex]

Initial Current [tex]I_1=1400A[/tex]

Force [tex]F=2.00N[/tex]

Distance of Wire [tex]d=4.50cm=>0.0450m[/tex]

Generally the equation for Force is mathematically given by

 [tex]F=\frac{\mu_0 * I_1*I_2*l_s}{2 \pi *r}[/tex]

 [tex]F=\frac{4 \pi*10^{-7} *1400 I*I_2*2.9}{2 \pi *0.0450}[/tex]

 [tex]I_2=\frac{22.5*10^-2}{2*10^{-7}*1400*2.6}[/tex]

 [tex]I_2=30.9A[/tex]

Answer:

f = 1 m

Explanation:

The magnification of the lens is given by the formula:

[tex]M = \frac{q}{p}[/tex]

where,

M = Magnification = 4

q = image distance = 5 m

p = object distance = ?

Therefore,

[tex]4 = \frac{5\ m}{p}\\\\p = \frac{5\ m}{4}\\\\p = 1.25\ m[/tex]

Now using thin lens formula:

[tex]\frac{1}{f}=\frac{1}{p}+\frac{1}{q}\\\\\frac{1}{f} = \frac{1}{1.25\ m}+\frac{1}{5\ m}\\\\\frac{1}{f} = 1\ m^{-1}\\\\[/tex]

f = 1 m

Explanation:

The period T of a simple pendulum is given by

[tex]T = 2 \pi \sqrt{\dfrac{l}{g}}[/tex]

Doubling the length of the pendulum gives us a new period T'

[tex]T' = 2 \pi \sqrt{\dfrac{l'}{g}} = 2 \pi \sqrt{\dfrac{2l}{g}}[/tex]

[tex]\:\:\:\:\:\:\:= \sqrt{2} \left(2 \pi \sqrt{\dfrac{l}{g}} \right)[/tex]

[tex]\:\:\:\:\:\:\:= \sqrt{2}\:T = \sqrt{2}(3.5\:\text{s})= 4.95\:\text{s}[/tex]

Answer:

Explanation:

a)

Below  the worker , the tension in cable  is pulling  the crate . Let the tension be T₁ .

weight of  crate is acting downwards .

Total weight  1510  N.

Net force acting on both = T₁ - 1510

Applying second law of Newton ,

T₁ - 1510 = 1510 / 9.8 x 0.62                [ 1510 / 9.8 = mass of  crate ]

T₁ - 1510 = 95.5

T₁  = 1605.5  N.

b )

Above the worker , the tension in cable  is pulling both the worker and the crate . Let the tension be T₂ .

weight of both worker and crate is acting downwards .

Total weight = 965 + 1510 = 2475 N.

Net force acting on both = T₂ - 2475

Applying second law of Newton ,

T₂ - 2475 = 2475 / 9.8 x 0.62  [ 2475 / 9.8 = mass of both worker and crate ]

T₂ - 2475 = 156.6

T₂  = 2631.6 N.

Answer:

a) the work (W) done during the process is -2043.25 kJ

b) the work (W) done during the process is -2418.96 kJ

Explanation:

Given the data in the question;

mass of water vapor m = 10 kg

initial pressure P₁ = 550 kPa

Initial temperature T₁ = 340 °C

steam cooled at constant pressure until 60 percent of it, by mass, condenses; x = 100% - 60% = 40% = 0.4

from superheated steam table

specific volume v₁ = 0.5092 m³/kg

so the properties of steam at p₂ = 550 kPa, and dryness fraction

x = 0.4

specific volume v₂ = v[tex]_f[/tex] + xv[tex]_{fg[/tex]

v₂ = 0.001097 + 0.4( 0.34261 - 0.001097 )

v₂ = 0.1377 m³/kg

Now, work done during the process;

W = mP₁( v₂ - v₁ )

W = 10 × 550( 0.1377 - 0.5092 )

W = 5500 × -0.3715

W = -2043.25 kJ

Therefore, the work (W) done during the process is -2043.25 kJ

( The negative, indicates work is done on the system )

b)

What would the work done be if steam were cooled at constant pressure until 80 percent of it, by mass, condenses

x₂ = 100% - 80% = 20% = 0.2

specific volume v₂ = v[tex]_f[/tex] + x₂v[tex]_{fg[/tex]

v₂ = 0.001097 + 0.2( 0.34261 - 0.001097 )

v₂ = 0.06939 m³/kg

Now, work done during the process will be;

W = mP₁( v₂ - v₁ )

W = 10 × 550( 0.06939 - 0.5092 )

W = 5500 × -0.43981

W = -2418.96 kJ

Therefore, the work (W) done during the process is -2418.96 kJ

Answer:

Explanation:

A coin and feather dropped in a moon experience the same acceleration due to gravity as small as 1.625 m/s², and because of the absence of air resistance both will fall at the same rate to the ground.

If the same coin and feather are dropped in the earth, they will experience the same acceleration due to gravity of 9.81 m/s² and because of the presence of air resistance, the heavier object (coin) will be pulled faster to the ground by gravity than the lighter object (feather).

Answer:

Look at work

Explanation:

Elastic Collision: Ki=Kf

M1=4.65kg

M2: 0.060kg

v1=5m/s

v2=0m/s

4.65*5+0.060*0=4.65*v1'+0.060*v2'

23.25+0=4.65v1'+0.060v2'

Also since it is an elastic collision we can use

v1+v1'=v2+v2'

4.65+v1'=v2'

4.65+v1'=v2'

Substitute into the earlier equation

23.25=4.65v1'+0.060(4.65+v1')

Expand

23.25=4.65v1'+0.279+0.06v1'

Solve for v1'

22.971=4.71v1'

v1'=4.88m/s

v2'=4.65+4.88=9.53m/s

Answer:

a)  v₀ = 44.27 m / s, b) stone A  v = 44.276 m / s,  stone B   v = 0.006 m / s

Explanation:

a) This is a kinematics exercise, let's start by finding the time it takes for stone A to reach half the height of the building y = 100 m

          y = y₀ + v₀ t - ½ gt²

as the stone is released its initial velocity is zero

         y- y₀ = 0 - ½ g t²

         t = [tex]\sqrt{ -2(y-y_o)/g}[/tex]

         t = [tex]\sqrt{ -2(100-200)/9.8}[/tex]

         t = 4.518 s

now we can find the initial velocity of stone B to reach this height at the same time

         y = y₀ + v₀ t - ½ g t²

stone B leaves the floor so its initial height is zero

         100 = 0 + v₀ 4.518 - ½ 9.8 4.518²

         100 = 4.518 v₀ - 100.02

         v₀ = [tex]\frac{100-100.02}{4.518}[/tex]

         v₀ = 44.27 m / s

b) the speed of the two stones at the meeting point

stone A

          v = v₀ - gt

          v = 0 - 9.8 4.518

          v = 44.276 m / s

stone B

          v = v₀ -g t

          v = 44.27 - 9.8 4.518

          v = 0.006 m / s

we know density = mass/ volume

as mass = 0.6 g

and volume = 2cm³

so density = (6/20)(g/cm³)

0.3g/cm³ (ans)

Hope it helps

Explanation:

Given

Acceleration of the pebble is

At t=0, velocity is

considering horizontal motion

[tex]\Rightarrow x=ut+0.5at^2 \\\Rightarrow 11=4.3t+0.5(4.6)t^2\\\Rightarrow 2.3t^2+4.3t-11=0\\\Rightarrow (t-1.4435)(t+3.3131)=0\\\Rightarrow t=1.44\ s\quad [\text{Neglecting negative time}]\\[/tex]

Velocity acquired during this time

[tex]\Rightarrow v_x=4.3+4.6\times 1.44\\\Rightarrow v_x=4.3+6.624\\\Rightarrow v_x=10.92\ s[/tex]

Consider vertical motion

[tex]\Rightarrow v_y=0+7(1.44)\\\Rightarrow v_y=10.08\ m/s[/tex]

Net velocity is

[tex]\Rightarrow v=\sqrt{10.92^2+10.08^2}\\\Rightarrow v=\sqrt{220.85}\\\Rightarrow v=14.86\ m/s[/tex]

Angle made is

[tex]\Rightarrow \tan \theta =\dfrac{10.08}{10.92}\\\\\Rightarrow \tan \theta =0.92307\\\\\Rightarrow \theta =42.7^{\circ}[/tex]

Answer:

6m/s

Explanation:

We are to calculate the speed of Monique

Speed = Distance/Time

Given

Distance = 360m

Time = 60secs

Substitute

Speed = 360m/60s

Soeed = 6m/s

Hence she was running at 6m/s

Answer:

v = 804.23 m/s

Explanation:

Given that,

The maximum distance covered by a cannon, d = 33 km = 33000 m

We need to find the initial velocity of the shell. Let it is v. It can be calculated using the conservation of energy such that,

[tex]v=\sqrt{2gh} \\\\v=\sqrt{2\times 9.8\times 33000} \\\\v=804.23\ m/s[/tex]

So, the initial velocity of the shell is 804.23 m/s.

Answer:

It is a example of physical change

Answer: See attached pic. Hope this helps.

Explanation:

Answer:

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Explanation:

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Answer:

[tex]\frac{a_{c1}}{a_{c2}} = 2.23[/tex]

Explanation:

The centripetal acceleration is given as follows:

[tex]a_c = \frac{v^2}{r}\\[/tex]

where,

ac = centripetal acceleration

v = linear speed = rω

r = radius

ω = angular speed

Therefore,

[tex]a_c = \frac{(r\omega)^2}{r}\\\\a_c = r\omega^2[/tex]

Therefore, the ratio will be:

[tex]\frac{a_{c1}}{a_{c2}} = \frac{r_1\omega^2}{r_2\omega^2}\\\\\frac{a_{c1}}{a_{c2}} = \frac{r_1}{r_2}\\\\[/tex]

where,

r₁ = 6.7 m

r₂ = 3 m

Therefore,

[tex]\frac{a_{c1}}{a_{c2}} = \frac{6.7\ m}{3\ m}\\\\[/tex]

[tex]\frac{a_{c1}}{a_{c2}} = 2.23[/tex]

Answer:

B. Smaller than

Explanation:

This question is from the Doppler effect. As the object which is in motion goes off from the other, there's a reduction in the frequency. This is due to the fact that successive soundwave get to be longer. So that the pitch will then be lowered. When the person observing moves towards what is making the sound, each soundwave that follows gets faster than the previous.

Answer:

how to solve this problem ???????

The magnitude of the resultant force is 919.6 N and the value of angle θ is 36.87⁰.

The resultant of the two forces is determined by resolving the force into x and y component as shown below;

[tex]F_1_x + F_2x_x = F_R_x \ --- (1) \\\\F_1_y + F_2_y = F_R_y\ ---(2)[/tex]

where;

The value of Angle θ is determined from equation (1)

-500sinθ + 600sin(30) = 0

500sinθ = 600sin(30)

500sinθ = 300

sinθ = 3/5

θ = 36.87⁰

The resultant of the forces is determined using the second equation;

500cosθ + 600cos(30) = R

500 x cos(36.87) + 600 x cos(30) = R

919.6 N = R

Learn more about resultant forces here: https://brainly.com/question/25239010

Answer:

when the mass of an object is decreased, the acceleration will increase

when mass is increased, acceleration decreases

Answer:

c

Explanation:

darker colors absorb app light

Answer:

C. Is absorbing all wavelengths of light.

Explanation:

Black isn't a color, but rather the absence of color. We see a T-shirt as black because it isn't reflecting any light toward our eyes. A black T-shirt absorbs all of the wavelengths of light, causing it to absorb more energy and become warmer than white, which reflects light.

Answer:

Distance between them after 5 hours is 300 km.

Explanation:

From point A a vehicle leaves at 80 km / h at the same time a cyclist leaves at 20 km / h at what distance is they from each other after 5 hours.

Distance traveled by A in 5 hours = speed x time = 80 x 5 = 400 km

Distance traveled by B in 5 hours = speed x time = 20 x 5 = 100 km

The distance between them after 5 hours =  400 - 100 = 300 km

Answer:

 E = 2,964 10⁻¹⁹ J

Explanation:

The energy of the photons is given by the Planck relation

          E = h f

the speed of light is related to wavelength and frequency

          c = λ f

we substitute

          E = h c /λ

let's reduce the magnitude to the SI system

          λ = 671 nm = 671 10⁻⁹ m

let's calculate

          E = 6.63 10⁻³⁴ 3 10⁸ /671 10⁻⁹

          E = 2,964 10⁻¹⁹ J

Answer:

the SI unit (meter per second square) indicates a linear type of motion.

Explanation:

Given;

acceleration of the car, a = 5.2 m/s² North

the SI unit of the car, = m/s²

The SI unit of the given value (acceleration), indicates a linear type of motion.

Linear acceleration is the change in linear velocity with time. Also, the northwards direction indicates linear displacement of the car.

Therefore, the SI unit (meter per second square) indicates a linear type of motion.

Answer:

displacement

Explanation:

Answer:

Images formed by a convex mirror are always ​virtual

Explanation:

A virtual image is always created by a convex mirror, and it is always situated behind the mirror. The picture is vertical and situated at the focus point when the item is far away from the mirror. As the thing approaches the mirror, the image follows suit and increases until it reaches the same height as the object.

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