Newton's Second Law (SMART)

A 750-newton person stands in an elevator that is accelerating downward. The upward force of the elevator floor on the person must be

• equal to 0 N

• less than 750 N

• equal to 750 N

• greater than 750 N

Four forces act concurrently on a block on a horizontal surface as shown in the diagram below

• moves at constant speed to the right

• moves at constant speed to the left

• accelerate to the right

• accelerate to the left

A 25-newton horizontal force northward and a 35-newton horizontal force southward act concurrently on a 15-kilogram object on a frictionless surface. What is the magnitude of the object's acceleration?

• 0.67 m/s²

• 1.7 m/s²

• 2.3 m/s²

• 4.0 m/s²

A net force of 25 Newtons is applied horizontally to a 10.-kilogram block resting on a table. What is the magnitude of the acceleration of the block?

• 0.0 m/s2

• 0.26 m/s2

• 0.40 m/s2

• 2.5 m/s2

A horizontal force is used to pull a 5.0-kilogram cart at a constant speed of 5.0 meters per second across the floor, as shown in the diagram below.

If the force of friction between the cart and the floor is 10. Newtons, the magnitude of the horizontal force along the handle of the cart is

• 5.0 N

• 10. N

• 25 N

• 50. N