A piece of rock was brought from the moon to earth. Then

A. its mass alone changed
B. its weight alone changed
C. both mass as well as weight changed
D. neither its mass nor its weight changed


A shell initially at rest suddenly explodes into two equal fragments A and B. Which one of the following is observed?

A. A and B moves in the same direction with the same speed
B. A and B moves in the same direction with different speed
C. A and B move in opposite direction with same speed
D. A and B move in opposite directions with different speed


A magnetic needle is kept in a non-uniform management field. It experiences

A. a force and a torque
B. a force but not a torque
C. a torque but not a force
D. neither a force nor a torque


A person climbing a hill bends forward in order to

A. avoid slipping
B. increase speed
C. reduce fatigue
D. increase stability


A hydrogen filled ballon rises in the air because

A. the atmospheric pressure decreases with altitude
B. the acceleration due to gravity decreases with altitude
C. the density of air decreases with altitude
D. the buoyant force excerted by the air on the balloon is greater than the weight of the balloon