NEET  >  Engineering Mechanics  >  Test: Work & Energy Download as PDF

Test: Work & Energy


Test Description

10 Questions MCQ Test Engineering Mechanics | Test: Work & Energy

Test: Work & Energy for NEET 2022 is part of Engineering Mechanics preparation. The Test: Work & Energy questions and answers have been prepared according to the NEET exam syllabus.The Test: Work & Energy MCQs are made for NEET 2022 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for Test: Work & Energy below.
Solutions of Test: Work & Energy questions in English are available as part of our Engineering Mechanics for NEET & Test: Work & Energy solutions in Hindi for Engineering Mechanics course. Download more important topics, notes, lectures and mock test series for NEET Exam by signing up for free. Attempt Test: Work & Energy | 10 questions in 10 minutes | Mock test for NEET preparation | Free important questions MCQ to study Engineering Mechanics for NEET Exam | Download free PDF with solutions
1 Crore+ students have signed up on EduRev. Have you?
Test: Work & Energy - Question 1

When a body falls freely under gravity, then the work done by the gravity is:

Detailed Solution for Test: Work & Energy - Question 1
  • If a force acting on a body has a component in the direction of displacement, then the work done by the force is positive.
  • Hence when a body falls freely under the influence of gravity the work done by gravity is positive.
Test: Work & Energy - Question 2

Raindrops fall on the earth with certain kinetic energy on the earth. From where do they get this energy?

Detailed Solution for Test: Work & Energy - Question 2

Every object that tends to fall or does fall on earth's surface does have a gravitational acceleration which is possessed by them due to their gravitational potential energy.

Test: Work & Energy - Question 3

Time rate at which work is done by a force is:

Detailed Solution for Test: Work & Energy - Question 3

We know that Work done, W = F.s
where F is force and s is displacement due to that force.
Thus rate of work done is: 

dW/dt = d(F.s)/dt

So as F is constant we get, 
dW/dt = F.d(s)/dt = F.v = P (Power)

Test: Work & Energy - Question 4

There are two bodies X and Y with equal kinetic energy but different masses m and 4m respectively. The ratio of their linear momentum is:

Detailed Solution for Test: Work & Energy - Question 4

X and Y have equal kinetic energy but their masses are m and 4m respectively.
► 1/2 m1v12 = 1/2 m2v22  
► mv12 = 4m * v22  
► v1 : v2 = 2 : 1
Hence the ratio of their linear momentum is:
m1v1 : m2v2 = m * 2v : 4m * v = 1 : 2

Test: Work & Energy - Question 5

A truck moves at a steady speed on a horizontal road. What is the work done by the road on the truck? 

Detailed Solution for Test: Work & Energy - Question 5

The work done is zero because while the truck does have a displacement over time, the force of the road (the normal force) is perpendicular and so the dot product of the two is zero.

Test: Work & Energy - Question 6

Output of a truck is 4500 J and its efficiency is 50%, the input energy provided to the truck is:

Detailed Solution for Test: Work & Energy - Question 6

► η = work output / heat input​
► η = 50% = 50/100 = 1/2
► 1/2 = 4500 / Heat input
► Heat input = 9000 J

Test: Work & Energy - Question 7

By how much does kinetic energy increase if the momentum is increased by 20%?

Detailed Solution for Test: Work & Energy - Question 7

The kinetic energy is given by: 

KE= p2/2m

So, ΔKE = 2pΔp​ / 2m = pΔp / m​
ΔKE / KE ​= (pΔp/m)​ * (2m/p2)​ = 2Δp / p
Since the momentum p increases by 20%, so the final momentum becomes 1.2p.
Hence, KEfinal​ = (1.2p)/ 2m​ = 1.44p2 / 2m​ = 1.44KE
So, % change in KE = 44%

Test: Work & Energy - Question 8

When a body slides against a rough horizontal surface, the work done by friction is:

Detailed Solution for Test: Work & Energy - Question 8
  • If a force acting on a body has a component in the opposite direction of displacement, the work done is negative.
  • So when a body slides against a rough horizontal surface, its displacement is opposite to that of the force of friction. The work done by the friction is negative.
Test: Work & Energy - Question 9

 A machine gun fires 60 bullets per minute, with a velocity of 700 m/s. If each bullet has a mass of 50g, find the power developed by the gun.

Detailed Solution for Test: Work & Energy - Question 9

Mass of the bullets = 60×50 = 3000g = 3kg
v = 700m/s t = 1min = 60s
Power = W/t = (Kinetic energy)/t = 12250W.

Test: Work & Energy - Question 10

 If a force acts perpendicular to the direction of motion of a body, what is the amount of work done?

Detailed Solution for Test: Work & Energy - Question 10

If a force acts perpendicular to the direction of a body, the amount of work done is zero because there is no displacement in the direction of a force.

24 videos|71 docs|39 tests
Use Code STAYHOME200 and get INR 200 additional OFF
Use Coupon Code
Information about Test: Work & Energy Page
In this test you can find the Exam questions for Test: Work & Energy solved & explained in the simplest way possible. Besides giving Questions and answers for Test: Work & Energy, EduRev gives you an ample number of Online tests for practice