Question

3) Which of the scenarios below involve an object experiencing zero net-force? [Enter your answer as a string of the letter options you believe are correct. For instance, if you think options A, D, and E are correct, then enter "ADE"]

A) A person pushes a car up a hill at a constant velocity.
B) You throw a book straight up off of a table.
C) A driver steadily accelerates in their car.
D) A particle's momentum is constant as it moves from one place to another.
E) None of the above

Answer 1

Answer :"AD"

Explanation:

As per Newtons second law net force on a body is proportional to rate of change of momentum of the body.

Now in

A)

As velocity is constant so momentum will also remain constant and thus no change in momentum, which implies no net force on body.

B) When book in thrown up then during its motion it will have acceleration due to gravity so net force is not zero.

C) As car is accelerating so momentum is changing and thus net force is acting on it.

D) As particles momentum is constant so no net force is acting on it.