Question

1)What is the mass of an object if a net force of 8.0 N causes it to accelerate at 1.1 m/s2?

6.9 kg
7.3 kg
8.8 kg
9.1 kg

2)For problems that involve an object accelerating along an inclined plane, how can the weight be used to determine the force component that causes motion?

The weight is the full force that acts perpendicular to the surface of the ramp.
The weight times the cosine of the ramp’s angle is the force perpendicular to the ramp.
The weight times the sine of the angle of the ramp acts down along the ramp.
The weight times the cosine of the angle of the ramp acts down along the ramp.

3)A rocket experiences a constant force even as the amount of fuel in its fuel tanks decreases. What happens to the acceleration of the rocket as it runs out of fuel?

The acceleration decreases because the mass increases.
The acceleration increases because the mass increases.
The acceleration decreases because the mass decreases.
The acceleration increases because the mass decreases.

4)Which quantity may be calculated directly using Newton’s second law of motion?

weight
velocity
position
direction

5)Juanita studies several free-body diagrams in which a normal force is shown. What is always true about a normal force in a free-body diagram?

It is opposite the weight.
It is perpendicular to a surface.
It is opposite the net force.
It is parallel to a surface.

6)A box that has a mass of 80 kg slides down a ramp with a 30 degree angle. The free-body diagram shows the forces acting on the box.
Ignoring friction and air resistance, what is the acceleration of the box, to the nearest tenth?

0.5 m/s2
4.9 m/s2
8.5 m/s2
9.8 m/s2
(the picture is for this question)

Answer 1

1) 7.3
3) acceleration decreases because mass decreases
4) weight

Answer 2

1) F=8
a=1.1
F=ma
m=F/a=8/1.1=80/11=7.3 kg