Q: A car rounds a banked curve of radius $$R at $$speed $$v$$ with no friction. What is the correct expression for the banking angle $$\beta so $$the car can make the turn?

$$\tan \beta = \frac{v^2$}{gR}$$

Question 1

A box of mass $$m is at $$rest on a horizontal surface. Which equation correctly represents the equilibrium condition for the forces acting on the box according to Newton's first law?

Accepted Answer

$$\sum F_x = 0$$ and $$\sum F_y = 0$$

Question 2

A passenger with mass $$m$$ stands on a scale in an elevator accelerating upward with acceleration $$a_y. $$What is the apparent weight shown by the scale?

Accepted Answer

$$n = m(g + a_y)$$

Question 3

A car rounds a banked curve of radius $$R at $$speed $$v$$ with no friction. What is the correct expression for the banking angle $$\beta so $$the car can make the turn?

Accepted Answer

$$	an \beta = \frac{v^2$}{gR}$$

Question 4

Which of the following statements about free-body diagrams is correct?

Accepted Answer

Only forces acting on the object should be included; $$ma is $$not a force.

Question 5

A block is pulled across a rough surface at constant speed. Which equation correctly describes the kinetic friction force?

Accepted Answer

$$f_k = \mu_k n$$

Question 6

A box is at rest and a weak force is applied. Which statement about static friction is correct?

Accepted Answer

$$f_s \u003c \mu_s n$$

Question 7

A falling object reaches terminal speed when:

Accepted Answer

The drag force equals the weight of the object.

Question 8

Which of the following is NOT a fundamental force of nature?

Accepted Answer

Frictional force

Question 9

A caterpillar moves forward due to friction between its feet and the surface. Which type of friction is primarily responsible for its movement?

Accepted Answer

Static friction

Question 10

An astronaut orbiting Earth experiences apparent weightlessness because:

Accepted Answer

The astronaut and spacecraft are in free fall, so the normal force is zero.

Question 11

A block is just about to slide on a surface. What is the maximum static friction force?

Accepted Answer

$$f_s = \mu_s n$$

Question 12

Which equation correctly represents Newton’s second law for the $$x-$$component of force?

Accepted Answer

$$\sum F_x = m a_x$$

Question 13

A car rounds a curve of radius $$R at $$speed $$v. $$What is the net force required for uniform circular motion?

Accepted Answer

$$F = m v^2$ / R$$

Question 14

If a string breaks while swinging a ball in a circle, what path does the ball follow?

Accepted Answer

It moves in a straight line tangent to the circle.

Question 15

Which statement about the stick-slip phenomenon in windshield wipers is correct?

Accepted Answer

The wiper blade sticks due to static friction, then slides when the force exceeds maximum static friction.

Question 16

A block is sliding at constant speed on a horizontal surface. Which statement is true about the forces acting on it?

Accepted Answer

The applied force equals the kinetic friction force.

Question 17

Which of the following is a common error in drawing free-body diagrams for circular motion?

Accepted Answer

Including $$m a as a $$force.

Question 18

A falling fruit is acted upon by which force(s)?

Accepted Answer

Only the force of gravity.

Question 19

When an object moves along a circular path, both its acceleration and net force are directed:

Accepted Answer

Toward the center of the circle.

Question 20

Which of the following best describes the relationship between friction and molecular interactions?

Accepted Answer

Friction arises from interactions between molecules on the surfaces in contact.

Applying Newton’s Laws: Equilibrium, Dynamics, Friction, Circular Motion, and Fundamental Forces

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