CHAPTER 5 TEST



CHAPTER 5 Review NAME________________________

HONORS PHYSICS

Answer the following questions as thoroughly as possible. Remember to define your know and unknown values, show the equation, substitute and solve. Make sure your answer has the correct units.

1. Mr. Bro decides to go golfing. He swings the club with a force of 1200 Newtons. The .050 kg ball flies into the woods (at least he got it in the air) at a speed of 54 m/s. How long was the ball in contact with the club?

F=1200 N t=mΔv/F t=(.050 kg)((54 m/s)/(1200 N) .0025 s

M=.050 kg

Δv=54 m/s

2. A rifle of mass 15 kg shoots a bullet of 10 grams at a speed of 1000 m/s. Find the recoil speed of the rifle.

Ma=15 kg MaVa=-MbVb (15 kg)(x)=-(.010kg)(1000m/s) -.667 m/s

Mb=.010 kg

Vb=1000 m/s

Va=?

3. A 20,000 kg truck is out of control and going down the street at 20 m/s. It hits the parked 1500 kg Toyota and they stick together. What is their combined speed after the collision?

Ma=20,000 kg

Va=20 m/s MaVa+MbVb=(Ma+Mb)Vfinal

Mb=1500 kg (20,000 kg)(20 m/s)+(1500kg)(0 m/s)=(20,000kg +1500 kg)Vfinal

Vb=0 m/s

Vfinal=? (400,000) + 0 =21,500 Vfinal Vfinal=400,000/21500 18.6 m/s

4. A 25 kg girl is sliding east across an ice-covered pond with a velocity of 15 m/s.

A 30 kg boy is sliding east across the same pond at 3 m/s in front of her. They collide and

stick together. What is their final velocity?

Ma=25 kg MaVa+MbVb=(Ma+Mb)Vfinal Vfinal=465/55 5.17 m/s

Va=15 m/s

Mb=30 kg (25)(15) + (30)(3)=(25+30)Vfinal

Vb=3 m/s

Vfinal=? 375 + 90 = (55)Vfinal

5. What impulse is needed to change the speed of a 25 kg object by 35 m/s?

M=25 kg I=MΔV =(25 kg)(35 m/s) 875 kgm/s

ΔV=35 m/s

I=?

6. A 25,000 kg truck is moving 30 m/s when it hits a parked 900 kg Toyota and they stick together. What is their new velocity?

Ma=25,000 kg MaVa+MbVb=(Ma+Mb)Vfinal Vfinal=28.96 m/s

Va=30 m/s

Mb=900 kg (25,000)(30) + (900)(0) = (25,900)Vfinal

Vb=0 m/s

Vfinal =? 750,000 + 0 =25,900Vfinal

7. A 700 kg cannon’s recoil velocity is measured to be 3 m/s. How fast did the 1.2 kg cannonball go?

Ma=700 kg MaVa=-MbVb (700)(3)=-(1.2)(x) x=-1750 m/s

Va=3 m/s \

Mb=1.2 kg

Vb=?

8. It takes 25 seconds for an 80 Newton force to stop an object moving 70 m/s. What was the mass of the object?

T=25 seconds m=Ft/V =(80)(25)/70 =28.6 m/s

F=80 Newtons

V=70 m/s

M=?

1. A rifle recoils while firing a bullet. Why is the speed of the rifle small compared to the speed of the bullet?

The rifle has a much greater mass. Therefore, for the momenta to be equal, it must move much slower.

2. A 1 kg chunk of putty moving at 1 m/s collides and sticks to a 5 kg bowling ball initially at rest. The bowling ball and putty then move with a momentum equal to __________1________kg m/s.

3. Two cars having the same mass move toward each other with the same speed. When they collide, what is their combined momentum? Zero, since momentum is a vector quantity, you must subtract their momentum or make one of them negative.

4. You are driving down the highway and you hit a bird. Which undergoes the greater change in momentum? Same Which undergoes the greater force? Same Which undergoes the greater acceleration? Bird (smaller mass)

5. An astronaut is floating in outer space when he throws a wrench. If the wrench moves away at a speed of 30 m/s, describe the motion of the astronaut.

The astronaut will move in the opposite direction at a slower speed.

Which direction is he moving? Opposite the wrench

Is he moving faster, slower or the same speed as the wrench? Slower-Bigger mass

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download