The kinetic energy acquires by a mass m in travelling distance d, starting from rest, under the action of a constant force is directly proportional to?
A.
m
B.
m0
C.
√m
D.
1/√m
Answer: Option B
Explanation:
v2-u2=2as v2-0=2×F/m×d = 2Fd/m Kinetic energy = 1/2 mv2=1/2 m×2Fd/m = Fd Hence, kinetic energy does not depend on m or it is directly proportional to m0.
A simple pendulum hanging freely and at rest is vertical because in that position?
A.
Kinetic energy is zero
B.
Potential energy is zero
C.
Kinetic energy is minimum
D.
Potential energy is minimum
Answer: Option D
Explanation:
In the position of equilibrium, the potential energy of the simple pendulum is minimum. Therefore a simple pendulum hanging freely and at rest is vertical because in that position potential energy is minimum.
A bullet is fired and gets embedded in a block kept on the table. If a table is frictionless, then?
A.
Kinetic energy gets conserved
B.
Potential energy gets conserved
C.
Momentum gets conserved
D.
Kinetic energy and potential energy gets conserved
Answer: Option C
Explanation:
Only momentum gets conserved when a bullet is fired and gets embedded in a block kept on a frictionless table. Some kinetic energy is lost when the bullet penetrates the block.
