HW_4_NOTES

How does acceleration depend on the net force?

Acceleration is proportional to the net force.

What does Dr. Hewitt do to drag the block across the table?

He applies a steadily increasing force.

If Dr. Hewitt applies 3N of force to keep the block moving at a steady rate, what must the force of friction be?

The force of friction should exactly balance out the force Dr. Hewitt applies.

What is the relationship between the force needed to keep an object in motion at a steady rate and applied force?

The applied force must equal the force of friction.

Which is normally greater, static friction or sliding friction?

Static friction is normally greater than sliding friction.

What is the net force acting on an object at rest?

The net force acting on it is zero.

What can you conclude about a block moving to the left at a constant velocity?

The net force applied to the block is zero.

What happens to the acceleration of an object if its mass increases, assuming a constant net force is applied?

The acceleration decreases.

What is Newton's First Law?

An object at rest cannot remain at rest unless the net force acting on it is zero.

What happens to the crate's velocity when the applied force goes to zero?

The crate's acceleration becomes zero and its velocity remains constant.

What is the minimum force that must be exerted on the crates for them to accelerate?

The minimum force must overcome any opposing friction.

How does the angle of the ramp affect static friction?

As the ramp angle increases, the force of static friction must increase.

What is the equation for weight?

Weight is calculated as weight = mass x gravitational acceleration (W = mg).

If the coefficient of friction is less than 0.7, what happens to the maximum ramp angle that allows the crate to remain at rest?

The angle at which the crate can remain at rest decreases.

Which forces must be included in a free body diagram of an apple?

The gravitational force from the Earth and the normal force.

Which experience a greater magnitude of force, the rifle or the bullet, during firing?

The forces are equal in magnitude but opposite in direction due to Newton's Third Law.

How does the acceleration of the bullet compare with the acceleration of the rifle?

The bullet has a greater magnitude of acceleration than the rifle.

Do you pull up on Earth with the same force that Earth pulls on you?

Yes, you pull up on Earth with the same force.