Question 1

A runner completes four full laps around a circular track with a radius of 200 m, starting and ending at the same point. What are the runner's displacement and distance traveled?

Accepted Answer

Displacement = $$0\ \mathrm{m}$$, Distance = $$1600\ \mathrm{m}$$

Question 2

A car accelerates uniformly from $$6.5\ \mathrm{m/s} to$$ $$1.5\ \mathrm{m/s} to $$the west in $$2.0\ \mathrm{s}$$, with an acceleration of $$2.5\ \mathrm{m/s^2$} to $$the west. How far did it travel during the acceleration?

Accepted Answer

$$8\ \mathrm{m}$$

Question 3

Which of the following is a vector quantity?

Accepted Answer

Displacement

Question 4

A ball is thrown horizontally from a $$45\ \mathrm{m}$$ high cliff and lands $$30\ \mathrm{m}$$ away from the base. What was the initial speed of the ball? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$6.6\ \mathrm{m/s}$$

Question 5

A cyclist travels $$2\ \mathrm{km}$$ north, then $$4\ \mathrm{km}$$ east, then $$2\ \mathrm{km}$$ south, and finally $$4\ \mathrm{km}$$ east. What is the magnitude of the cyclist's displacement?

Accepted Answer

$$6\ \mathrm{km}$$

Question 6

A projectile is launched at $$20\ \mathrm{m/s} at an $$angle of $$30^\circ$$ above the horizontal. What is the initial vertical component of its velocity?

Accepted Answer

$$10.0\ \mathrm{m/s}$$

Question 7

A cat runs at $$2\ \mathrm{m/s} to $$the right on a treadmill moving at $$3\ \mathrm{m/s} to $$the right. What is the cat's velocity relative to the ground?

Accepted Answer

$$5\ \mathrm{m/s}$$\ to\ the\ right

Question 8

A hiker walks $$6\ \mathrm{km} at$$ $$15^\circ$$ above the horizontal, then $$2\ \mathrm{km} at$$ $$30^\circ$$ above the horizontal. What is the best method to find the hiker's resultant displacement?

Accepted Answer

Resolve each displacement into x and y components, sum the components, then use the Pythagorean theorem and inverse tangent.

Question 9

Which kinematic equation would you use to find the displacement $$\Delta x of an $$object with initial velocity $$v_0$$, constant acceleration $$a$$, and time $$t$$?

Accepted Answer

$$\Delta x = v_0$ t + \frac{1}{2} a t^2$

Question 10

A stone is dropped from rest from a bridge and hits the water after $$2.0\ \mathrm{s}. $$What is the height of the bridge? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$39.2\ \mathrm{m}$$

Question 11

A plane flies at $$250\ \mathrm{m/s}$$ northwest into a $$30\ \mathrm{m/s}$$ wind blowing southeast. What is the plane's speed relative to the ground?

Accepted Answer

$$220\ \mathrm{m/s}$$

Question 12

On a position-time graph, what does the slope at any point represent?

Accepted Answer

The instantaneous velocity

Question 13

A projectile is launched and lands at the same height. At the top of its trajectory, what is true about its vertical velocity?

Accepted Answer

It is zero

Question 14

A car enters a freeway at $$6.4\ \mathrm{m/s}$$ and accelerates uniformly for $$3.5\ \mathrm{min}$$, covering $$3.2\ \mathrm{km}. $$What is its final speed?

Accepted Answer

$$16.6\ \mathrm{m/s}$$

Question 15

Which of the following statements about free fall is correct?

Accepted Answer

All objects near Earth's surface fall with the same constant acceleration, regardless of mass.

Question 16

A badminton birdie is accelerated at $$2\ \mathrm{m/s^2$} by $$wind at $$5^\circ$$ below the horizontal, while gravity accelerates it at $$9.8\ \mathrm{m/s^2$}$$ downward. What is the magnitude of the resultant acceleration?

Accepted Answer

$$10.0\ \mathrm{m/s^2$}$$

Question 17

A dog stands $$2\ \mathrm{m} in $$front of you before you throw a ball $$10\ \mathrm{m}$$ away. The dog retrieves the ball and returns directly to you. What is the dog's displacement and distance traveled?

Accepted Answer

Displacement = $$2\ \mathrm{m}$$, Distance = $$22\ \mathrm{m}$$

Question 18

Which of the following best describes the difference between speed and velocity?

Accepted Answer

Speed is a scalar; velocity is a vector.

Kinematics: Motion in One and Two Dimensions

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