Physics of Inclined Planes Quiz

Answer explanation

The gravitational force acting on an object on an inclined plane can be resolved into two components: parallel and perpendicular. The component parallel to the incline is given by (mg sin theta), making this the correct choice.

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-4

Answer explanation

The acceleration of the block down the incline is determined by the component of gravitational force acting along the incline. This force is given by mg sin theta, leading to an acceleration of g sin theta.

Tags

NGSS.HS-PS2-1

A 5 kg block slides down a 30-degree incline with a coefficient of kinetic friction of 0.2. What is the net force acting on the block?

• 25 N

• 20 N

• 16 N

• 10 N

Answer explanation

To find the net force, calculate the gravitational force down the incline (Fg = mg sin(30°)) and the frictional force (Ff = μFn, where Fn = mg cos(30°)). The net force is Fg - Ff, resulting in 16 N.

Tags

NGSS.HS-PS2-1

If a block slides down an inclined plane with a constant speed, what can be said about the forces acting on it?

• The perpendicular component of gravitational force is equal to the frictional force.

• The frictional force is greater than the gravitational force.

• The parallel component of gravitational force is equal to the frictional force.

• There are no forces acting on the block.

Answer explanation

When a block slides down an inclined plane at constant speed, the net force is zero. This means the parallel component of gravitational force equals the frictional force, balancing each other out.

Tags

NGSS.HS-PS2-1

What is the work done by the gravitational force when a 10 kg block slides 5 meters down a frictionless incline of 30 degrees?

• (Fg)(length)

• (Fg cos theta)(length)

• (Fg sin theta)(length)

• (mass)(length)

Answer explanation

The work done by gravity on the incline is calculated using the component of gravitational force acting along the incline, which is Fg sin(theta) and the distance over which that force acts. Thus, the correct expression is (Fg sin theta)(length).

Tags

NGSS.HS-PS2-4

Which of the following statements is true about energy conservation on an inclined plane?

• Potential energy is always conserved.

• Kinetic energy is always conserved.

• Total mechanical energy is conserved if there is no friction.

• Total mechanical energy is conserved only if there is friction.

Answer explanation

Total mechanical energy is conserved on an inclined plane when there is no friction, as potential and kinetic energy can transform into each other without loss. Friction causes energy dissipation, violating conservation.

A block slides down a ramp at a constant speed. What is the value of the coefficient of friction between the ramp and block?

• cos theta

• sin theta

• tan theta

• zero

Answer explanation

The block slides down at constant speed, meaning friction balances the component of gravitational force along the ramp. The coefficient of friction is equal to the tangent of the ramp angle (tan theta), which relates to this balance.

To calculate the potential energy change of a 2 kg block that moves 3 meters up a 45-degree incline, what distance would you use?

• length of ramp (3 m)

• height of ramp (3 cos 30 m)

• height of ramp (3 sin 30 m)

• height of ramp (3 tan 30 m)

Answer explanation

To find the potential energy change, we need the vertical height gained. The height is calculated using the sine function: height = 3 m * sin(30°). Thus, the correct choice is height of ramp (3 sin 30 m).