Dynamics

A net force F accelerates a mass m with an acceleration a. If a net force 4F is applied to mass 5m, then the acceleration will be

• 5a

• 4a

• 5a/4

• 4a/5

You are in culinary and you drop a pie on the floor. Which of the following statements is true about the collision?

• the force on the pie is greater than the force on the floor

• the force on the floor is greater than the force on the pie

• The force on the pie is the same in maginitude as the force on the floor

• during the collision the pie has greater displacement than the floor

• during the collision the floor has a greater acceleration than the pie

When a soccer ball is hit by a foot, the force of the foot on the ball is equal and opposite to the force of the ball on the foot. This is an example of

• Newton's 1st Law

• Newton's 2nd Law

• The Law of Inertia

• Newton's 3rd Law

A plane travelling at 200 m/s strakies a fly. Which of the following is the true statement?

• The force on the fly is greater than the force on the plane

• The force on the fly is equal to the force on the plane

• The force on the fly is smaller than the force on the plan

• The damage to the fly is equal to the damage to the plane

An elevator of mass M is accelerated upwards by a cable. What is the tension in the cable?

• less than zero

• between zero and Mg

• equal to Mg

• greater than Mg

• zero

Why is it easy to keep an keep an object moving, once you got it started moving?

• μ_s < μ_k

• μ_s = μ_k

• μ_s > μ_k

• μ_s = 0

• the normal force is greater for objects at rest

The acceleration due to gravity on Jupiter is 1/4 less than on Earth. The mass and weight of a rock on Jupiter compared to that on Earth would be

• same, same

• 1/4 less, same

• same, 1/4 less

• 1/4 less. 1/4 less