Q: Every year the Earth travels about $$10^9 km as it $$orbits the Sun. What is Earth's average speed in km/h?

$$1 \times 10^5$ \ \mathrm{km/h}$$

Q: A light plane must reach a speed of $$35 \ \mathrm{m/s}$$ for takeoff. How long a runway is needed if the (constant) acceleration is $$3.0 \ \mathrm{m/s^2$}$$?

$$2.0 \times 10^2$ \ \mathrm{m}$$

Question 1

A driver is traveling at 95 km/h and glances away from the road for 2.0 s. How far does the car travel during this period? (Use $$1 \ \mathrm{h} = 3600 \ \mathrm{s})$$

Accepted Answer

$$53 \ \mathrm{m}$$

Question 2

What must your car's average speed be in order to travel 235 km in 2.75 h?

Accepted Answer

$$85.5 \ \mathrm{km/h}$$

Question 3

A particle moves from $$x_1 = 4.8$$ \ \mathrm{cm}$$ at t_1$ = -2.0 \ \mathrm{s} to$$ $$x_2 = 8.5$$ \ \mathrm{cm}$$ at t_2$ = 4.5 \ \mathrm{s}. $$What is its average velocity?

Accepted Answer

$$0.57 \ \mathrm{cm/s}$$

Question 4

A rolling ball moves from $$x_1 = 8.4$$ \ \mathrm{cm}$$ to x_2$ = -4.2 \ \mathrm{cm}$$ during the time from $$t_1 = 3.0$$ \ \mathrm{s}$$ to t_2$ = 6.1 \ \mathrm{s}. $$What is its average velocity?

Accepted Answer

$$-4.1 \ \mathrm{cm/s}$$

Question 5

A horse trots 38 m away from its trainer in 9.0 s, then gallops halfway back in 1.8 s. What is its average speed for the entire trip?

Accepted Answer

$$5.3 \ \mathrm{m/s}$$

Question 6

Every year the Earth travels about $$10^9 km as it $$orbits the Sun. What is Earth's average speed in km/h?

Accepted Answer

$$1 	imes 10^5$ \ \mathrm{km/h}$$

Question 7

A car accelerates from rest to 95 km/h in 4.3 s. What is its average acceleration in $$\mathrm{m/s^2$}$$?

Accepted Answer

$$6.1 \ \mathrm{m/s^2$}$$

Question 8

A sprinter accelerates from rest to $$9.00 \ \mathrm{m/s} in$$ $$1.38 \ \mathrm{s}. $$What is her acceleration in $$\mathrm{m/s^2$}$$?

Accepted Answer

$$6.52 \ \mathrm{m/s^2$}$$

Question 9

At highway speeds, a car can accelerate at $$1.8 \ \mathrm{m/s^2$}. $$How long does it take to accelerate from $$65 \ \mathrm{km/h} to$$ $$120 \ \mathrm{km/h}$$?

Accepted Answer

$$8.5 \ \mathrm{s}$$

Question 10

A car slows down from $$28 \ \mathrm{m/s} to $$rest in a distance of $$88 \ \mathrm{m}. $$What was its acceleration, assumed constant?

Accepted Answer

$$-4.5 \ \mathrm{m/s^2$}$$

Question 11

A car accelerates from $$14 \ \mathrm{m/s} to$$ $$21 \ \mathrm{m/s} in$$ $$6.0 \ \mathrm{s}. $$What is its acceleration?

Accepted Answer

$$1.17 \ \mathrm{m/s^2$}$$

Question 12

A light plane must reach a speed of $$35 \ \mathrm{m/s}$$ for takeoff. How long a runway is needed if the (constant) acceleration is $$3.0 \ \mathrm{m/s^2$}$$?

Accepted Answer

$$2.0 	imes 10^2$ \ \mathrm{m}$$

Question 13

A world-class sprinter can reach a top speed of $$11.5 \ \mathrm{m/s} in $$the first $$18.0 \ \mathrm{m} of a $$race. What is her average acceleration?

Accepted Answer

$$3.67 \ \mathrm{m/s^2$}$$

Question 14

A car leaves skid marks $$65 \ \mathrm{m}$$ long on the highway. Assuming a deceleration of $$4.00 \ \mathrm{m/s^2$}$$, estimate the speed of the car just before braking.

Accepted Answer

$$23 \ \mathrm{m/s}$$

Question 15

A car traveling $$75 \ \mathrm{km/h}$$ slows down at a constant $$0.50 \ \mathrm{m/s^2$} by$$ 'letting up on the gas.' How far does the car coast before it stops?

Accepted Answer

$$430 \ \mathrm{m}$$

Question 16

A space vehicle accelerates uniformly from $$85 \ \mathrm{m/s} at$$ $$t = 0 to$$ $$162 \ \mathrm{m/s} at$$ $$t = 10.0 \ \mathrm{s}. $$How far did it move between $$t = 2.0 \ \mathrm{s}$$ and $$t = 6.0 \ \mathrm{s}$$?

Accepted Answer

$$460 \ \mathrm{m}$$

Question 17

A stone is dropped from the top of a cliff and hits the ground after $$3.55 \ \mathrm{s}. $$How high is the cliff? (Assume $$g = 9.80 \ \mathrm{m/s^2$})$$

Accepted Answer

$$61.8 \ \mathrm{m}$$

Question 18

Estimate (a) how long it took King Kong to fall straight down from the top of the Empire State Building ($$380 \ \mathrm{m}$$ high), and (b) his velocity just before 'landing.' (Assume $$g = 9.80 \ \mathrm{m/s^2$})$$

Accepted Answer

Time: $$8.8 \ \mathrm{s}$$, Velocity: $$86 \ \mathrm{m/s}$$

Question 19

A baseball is hit almost straight up into the air with a speed of $$25 \ \mathrm{m/s}. $$Estimate (a) how high it goes, (b) how long it is in the air. (Ignore air resistance, $$g = 9.80 \ \mathrm{m/s^2$})$$

Accepted Answer

Height: $$32 \ \mathrm{m}$$, Time: $$5.1 \ \mathrm{s}$$

Question 20

The best rebounders in basketball have a vertical leap of about $$120 \ \mathrm{cm}. $$What is their initial 'launch' speed off the ground?

Accepted Answer

$$4.8 \ \mathrm{m/s}$$

Motion in One Dimension: Problems and Solutions

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