# Physics GK 05 - Work, Energy and Power

1. Which of the following is NOT correct about an inelastic collision?

[A] Linear momentum is conserved

[B] Kinetic energy is conserved

[C] Total energy is conserved

[D] Some or all the forces involved may be non-conservative in nature

[B] Kinetic energy is conserved

[C] Total energy is conserved

[D] Some or all the forces involved may be non-conservative in nature

2. The dot product of two vectors A and B is equal to the product of magnitude of A and B and __________?

[A] cosine of the largest angle between them

[B] sine of the largest angle between them

[C] cosine of the smallest angle between them

[D] sine of the smallest angle between them

[B] sine of the largest angle between them

[C] cosine of the smallest angle between them

[D] sine of the smallest angle between them

3. What is the dot product of two perpendicular vectors?

[A] 1

[B] 0

[C] -1

[D] 1/2

[B] 0

[C] -1

[D] 1/2

4. Work done is defined as the dot product of which of the following vectors?

[A] Force and acceleration

[B] Force and area

[C] Force and instantaneous velocity

[D] Force and displacement

[B] Force and area

[C] Force and instantaneous velocity

[D] Force and displacement

5. What is the dimensional formula of work done?

[A] M

[B] M

[C] M

[D] M

^{1}L^{1}T^{-1}[B] M

^{1}L^{2}T^{-1}[C] M

^{1}L^{-1}T^{-2}[D] M

^{1}L^{2}T^{-2}6. Which of the following is NOT correct about units of work:

[A] 1 joule = 10

[B] 1 kg-m = 1 joule

[C] 1 kg-m = 9.8 joule

[D] 1 joule = 1 Nm

^{7}ergs[B] 1 kg-m = 1 joule

[C] 1 kg-m = 9.8 joule

[D] 1 joule = 1 Nm

7. Work done will NOT be zero in which of the following case/cases?

[A] When displacement is zero

[B] When angle between force and displacement vector is zero

[C] When angle between force and displacement vector is 90°

[D] When force is zero

[B] When angle between force and displacement vector is zero

[C] When angle between force and displacement vector is 90°

[D] When force is zero

8. The work done by a variable force is given by:

[A] area under the force curve and the displacement axis

[B] square of the area under the force curve and the displacement axis

[C] natural log of the area under the force curve and the displacement axis

[D] twice the area under the force curve and the displacement axis

[B] square of the area under the force curve and the displacement axis

[C] natural log of the area under the force curve and the displacement axis

[D] twice the area under the force curve and the displacement axis

9. Which of the following is NOT a conservative force?

[A] Electrostatic force

[B] Magnetic force

[C] Force in an elastic spring

[D] Frictional force

[B] Magnetic force

[C] Force in an elastic spring

[D] Frictional force

10. The work done in moving a body over a smooth inclined plane does not depend on which of the following?

[A] mass of the body

[B] height of the inclined plane

[C] slope of the inclined plane

[D] All of the above

[B] height of the inclined plane

[C] slope of the inclined plane

[D] All of the above