MasteringPhysics CH 02 HW

22 m

A bus leaves an intersection accelerating at +2.0 m/s^2. Where is the bus after 4.7 s?

22 m/s

A person holding a lunch bag is moving upward in a hot air balloon at a constant speed of 7.9 m/s. When the balloon is 22 m above the ground, she accidentally releases the bag. What is the speed of the bag just before it reaches the ground?

0 m/s

Consulting the graph shown in the figure, find the object's average velocity over the time interval from 0 to 1 second.

20 m/s

Find the average velocity over the time interval from 1 to 3 seconds.

-13.3 m/s

Find the average velocity over the time interval from 3 to 6 seconds.

0 m/s

Find the average velocity over the whole time interval shown in the graph.

10.8 s

Imagine that a sprinter accelerates from rest to a maximum speed of 10.2 m/s in 2.0 s. In what time interval will he finish the 100-m race if he keeps his speed constant at 10.2 m/s for the last part of the race?

4.2 cm

Lolliguncula brevis squid use a form of jet propulsion to swim -- they eject water out of jets that can point in different directions, allowing them to change direction quickly. When swimming at a speed of 0.15 m/s or greater, they can accelerate at 1.2 m/s^2. Determine the distance, in cm, the squid has traveled while accelerating.

no

Two cars travel on the parallel lanes of a two-lane road. The cars' motions are represented by the position versus time graph shown in the figure. Answer the questions using the times from the graph indicated by letters. Are the two cars traveling in the same direction when they pass each other?

A

Two cars travel on the parallel lanes of a two-lane road. The cars' motions are represented by the position versus time graph shown in the figure. Answer the questions using the times from the graph indicated by letters. At which of the lettered times are the cars moving with nearly identical velocity?

C

Two cars travel on the parallel lanes of a two-lane road. The cars' motions are represented by the position versus time graph shown in the figure. Answer the questions using the times from the graph indicated by letters. At which of the lettered times, if any, does car #2 momentarily stop?

D

Two cars travel on the parallel lanes of a two-lane road. The cars' motions are represented by the position versus time graph shown in the figure. Answer the questions using the times from the graph indicated by letters. At which of the times do the two cars pass each other?

0.075 m/s^2

What is the average acceleration a of the particle over the first 20.0 seconds?

0.600 m/s

What is the average velocity v of the particle over the time interval Δt = 50.0s?

75 m

What is the displacement Δx of the particle?

0.5 m/s

What is the initial velocity of the particle, v0?

-0.20 m/s^2

What is the instantaneous acceleration a of the particle at t=45.0s?

0.600 m/s

What is the instantaneous velocity v of the particle at t=10.0s?

0.146 s

You are doing an experiment to determine your reaction time. Your friend holds a ruler. You place your fingers near the sides of the lower part of the ruler without touching it. The friend drops the ruler without warning you. You catch the ruler after it falls 10.4 cm. What was your reaction time?

13 m

You are driving a car behind another car. Both cars are moving at speed 80 km/h. Assume your brakes are just a bit harder than the car ahead and your reaction time is 0.60 s. What minimum distance behind the car in front should you drive so that you do not crash into the car's rear end if the driver of that car slams on the brakes?

1.2 s

You throw a tennis ball straight upward. The initial speed is about 12 m/s. How long will it take for the ball to reach its maximum height?

yes

You throw a tennis ball straight upward. The initial speed is about 12 m/s. Is 12 m/s a realistic speed for an object that you can throw with your hands?

7.3 m

You throw a tennis ball straight upward. The initial speed is about 12 m/s. What is the maximum height that the ball will reach? The initial position of the ball is at the height y0 = 0 m.

0.17 s

Lolliguncula brevis squid use a form of jet propulsion to swim -- they eject water out of jets that can point in different directions, allowing them to change direction quickly. When swimming at a speed of 0.15 m/s or greater, they can accelerate at 1.2 m/s^2. Determine the time interval needed for a squid to increase its speed from 0.15 m/s to 0.35 m/s.

30 m

What is the overall displacement Δx of the particle?