Question

1. which situation shows conservation of momentum?

a. a rocket floating
b. two skaters pushing apart
c. a book resting
d. a balloon popping

1. a fast baseball has more momentum than a slow baseball because it has more

a. time
b. speed
c. weight
d. volume

1. a system with no outside forces is called:

a. balanced
b. closed
c. open
d. heavy

1. two cars collide and stick together. their momentum is:

a. added together
b. lost
c. reduced to zero
d. increased

1. which factor does not affect momentum?

a. mass
b. speed
c. temperature
d. direction (only the sign changes)

1. if mass stays the same but speed doubles, momentum will:

a. stay the same
b. double
c. triple
d. drop to zero

Explanation:

Question 45

Conservation of momentum occurs in a closed system with no external forces. When two skaters push apart, the system (skaters) has internal forces, and if we consider them as a closed system (ignoring friction briefly), momentum is conserved. A rocket floating has gravity (external force), a book resting has normal and gravity (but no motion change related to momentum conservation in the sense of interaction), and a balloon popping has external air forces. So option B is correct.

Momentum \( p = mv \) (mass times velocity/speed). A fast baseball has more speed, so more momentum. Time, weight (mass is related but weight is force), and volume don't directly affect momentum as per the formula. So option B is correct.

A closed system in physics is one with no outside (external) forces acting on it. Balanced refers to forces being equal, open has external forces, heavy is about mass. So option B is correct.

Answer:

B. Two skaters pushing apart

Question 46