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2 years ago

A 1500 kg car, initially traveling at 22.0 m/s, hits its brakes and skids to a stop. Determine the work done by friction.

Physics

1 answer:

Sedbober [7]2 years ago

8 0

Answer:

The work done by the car is 363 kJ

Explanation:

Work : Work is said to be done when a Force moves an object through a certain distance. Work and Energy are interchangeable because they have the same unit. The unit of work is Joules (J).

Mathematically work done can be expressed as,

E = W = 1/2mv²

W = 1/2mv²................................ Equation 1

Where E = Energy, W = work done, m = mass of the car, v = velocity of the car

Given: m=1500 kg, v=22 m/s

Substituting these values into equation 1

W = 1/2(1500)(22)²

W = 750 × 484

W = 363000 J

W = 363 kJ

Thus the work done by the car is 363 kJ

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3 years ago

If a boat and its riders have a mass of 1100 kg and the boat drifts in at 1.3 m/s how much work does Sam do to stop it

andriy [413]

Answer:

-929.5Joules

Explanation:

To get the work done by sam, we will calculate the kinetic energy of sam expressed as;

KE = 1/2mv²

m is the mass = 1100kg

v is the velocity = 1.3m/s

KE = 1/2(1100)(1.3)²

KE = 550(1.69)

KE = 929.5Joules

Since Sam is opposing the direction of movement, work done by him will be a negative work i.e -929.5Joules

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3 years ago

Which transfer of energy occurs mainly through the process of convection?

Olegator [25]

Heat due to the amount of density difference within a fluid

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3 years ago

Type the correct answer in the box. Spell all words correctly. Complete the sentence using the correct term. A ______enforces fe

Goshia [24]

Answer:

Environmental Protection Agency (EPA)

Explanation:

In the United States of America, the agency which was established by US Congress and saddled with the responsibility of overseeing all aspects of pollution, environmental clean up, pesticide use, contamination, natural resources and hazardous waste spills is the Environmental Protection Agency (EPA). Also, EPA research solutions, policy development, and enforcement of regulations through the resource Conservation and Recovery Act.

The Environmental Protection Agency (EPA) is the governmental agency set up to ensure that various industries, factories and people comply with laws and regulations concerning the environment i.e it is an agency established to oversee and enforce environmental compliance by the people.

Hence, the Environmental Protection Agency (EPA) is saddled with the responsibility of enforcing federal and state laws related to environmental and natural resources.

7 0

2 years ago

A kangaroo can jump over an object 2.46 m high. (a) Calculate its vertical speed (in m/s) when it leaves the ground.

Elenna [48]

Answer:

a) 6.95 m/s

b) 1.42 seconds

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration due to gravity = 9.81 m/s²

$v^2-u^2=2as\\\Rightarrow -u^2=2as-v^2\\\Rightarrow -u^2=2\times -9.81\times 2.46-0^2\\\Rightarrow u=\sqrt{2\times 9.81\times 2.46}\\\Rightarrow u=6.95\ m/s$

a) The vertical speed when it leaves the ground. is 6.95 m/s

$v=u+at\\\Rightarrow t=\frac{v-u}{a}\\\Rightarrow t=\frac{0-6.95}{-9.81}\\\Rightarrow t=0.71\ s$

Time taken to reach the maximum height is 0.71 seconds

$s=ut+\frac{1}{2}at^2\\\Rightarrow 2.46=0t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow t=\sqrt{\frac{2.46\times 2}{9.81}}\\\Rightarrow t=0.71\ s$

Time taken to reach the ground from the maximum height is 0.71 seconds

b) Time it stayed in the air is 0.71+0.71 = 1.42 seconds

3 0

3 years ago