SAT Newton's laws:Quiz 5

A car accelerates from rest to a velocity of 20 meters per second. When it reaches this velocity, the driver removes his foot from the accelerator. Assume air resistance is negligible. The car will

• speed up slightly due to its inertia

• slow due to the lack of forward force

• come to a stop

• continue at 20 m/s briefly and then slow

• continue at 20 m/s until an unbalanced force acts on the car

A small object is attracted to Earth by a 50-newton gravitational force. The object pulls back on Earth with

• a force of 0 N

• a negligible, small nonzero force

• a force of 5 N

• a force of 50 N

• a force of 500 N

When an object is thrown upward in the absence of air resistance and reaches the top of its trajectory, it has an instantaneous velocity of zero. At this point, the net force acting on the object is

• zero

• equal to the weight of the object

• equal to the mass of the object

• g

• changing direction

Two strings support a 10-newton object, as shown above. The tension in string 1 is

• zero

• between 0 and 5 N

• 5 N

• between 5 and 10 N

• 10 N

A 70-kilogram person rides in an elevator that is accelerating upward at 2.0 meters per second squared. What is the normal force acting on the person?

• 560 N

• 700N

• 840N

• 960N

• 1000N

A mass remains at rest on an incline, as shown above. Which free-body diagram is correct?

• 
• 
• 
• 
• 

A mass, m, is pulled along a rough horizontal surface, as shown above. If the mass is accelerating, then the friction force, f, is equal to

• F only

• N only

• µmg only

• both A and C

• both B and C

A mass, m, is pulled along a horizontal surface by force F, as shown above. If the resulting motion is constant velocity, then the frictional force is equal to

• zero

• µmg

• mg cos θ

• F cos θ

• F sin θ

Three masses are connected with strings, as shown above. Determine the acceleration of the 2-kilogram mass.

• $0\frac{m}{s^2}$

• $1\frac{m}{s^2}$

• $2\frac{m}{s^2}$

• $4\frac{m}{s^2}$

• $6\frac{m}{s^2}$

As shown in the diagram above, a 2-kilogram mass lies on a horizontal rough surface while a 1-kilogram mass hangs vertically. The string between them is massless, and the pulley is both massless and frictionless. What minimum coefficient of friction will keep the blocks at rest?

• 0.1

• 0.2

• 0.3

• 0.4

• 0.5