VELOCITY:

1)What is the speed of a rocket that travels 9000 meters in 12.12 seconds?

d=vt   (distance = velocity multiplied by time)

          d=9000 m           t=12.12 sec.           solving for v,  v=d/t,

          v=742.57 m/sec.

2)What is the speed of a jet plane that travels 528 meters in 4 seconds?

d=vt

          d=528 m           t=4 sec           solving for v, v=d/t,

          v=132 m/sec.

3)After an impact involving a non-functioning satellite, a paint chip leaves the surface of the satellite at a speed of 96 m/s. After 17 seconds, how far has the chip landed?

d=vtv=96 m/sec.t=17 sec.

 d=1632 sec.

4)The space shuttle Endeavor is launched to altitude of 500 km above the surface of

the earth. The shuttle travels at an average rate of 700 m/s. How long will it take for Endeavor to reach its orbit?

d=vt

           d=500,000 m           v=700 m/sec.           solving for t, t=d/v,

           t=714.3 sec.(11.9 min.)

5) How long will your trip take (in hours) if you travel 350 km at an average speed of 80 km/hr?

.  

d=vt

           d=350,000 m           v=80,000 m/hr.           solving for t, t=d/v

           t=4.375 hrs.

ACCELERATION

1) While drag racing out of our school parking lot, I time myself at a speed of 40 meters per second seven

seconds after starting. What was my acceleration during this time?

Acceleration = (40 m/s) / 7 s = 5.7 m/s/2) Using this information, how far have I gone during this seven seconds?

d = ½ at2 = ½ (5.7 m/s/s)(7s)2 = 140 meters3)If I were to accelerate at this rate for another ninety seconds, how fast would I be going?

v = at = (5.7 m/s/s)(97 sec) = 550 m/s4) If I were to drop a ball out of my car while I was traveling at a velocity of 25 m/s, and it underwent a deceleration of 2.0 m/s/s while rolling to a stop, how long would it take for it to stop? 12.5 s

12.5 s

5) How far would it roll in this time?

d = ½ at2 = ½ (2.0 m/s/s)(12.5 s)2 = 156 mNote: correctly say that the acceleration of the ball is -2.0

m/s/s rather than the 2.0 m/s/s that I used in this problem. When you use this number, you get an answer of -156 m, which suggests that the ball moves backwards 156 meters. This doesn’t make sense, because the ball actually rolls forwards from where it was dropped. To simplify the idea here, use the idea of absolute value to describe distance.

FORCE:

1)A 3.5 kg. mass is travelling at a constant velocity of 25 m/s. What force is required to slow it to a stop in 5 seconds?

The answer is: 17.5 N

First, derive the acceleration by using the equation vf=vi + a*t

Using the derived value, multiply the acceleration by the mass of the object (F=m*a) The Result is the answer.

2. A 42 kg. mass is resting on the Earth's surface. What force does it exert on the Earth?

The answer is 412 N

All objects accelerate downwards, towards the Earth, due to gravity.

The rate of this acceleration is -9.81 meter per second per second.

Thus, using Newtons Second Law, F=m*a, Multiply the mass of the object by the rate of acceleration

3)A man wants to lift a crate full of pineapples. The crate weighs 230 kg. What force is required to lift it (at a constant velocity) straight up?

The answer is 2300 N

The force required to lift the box must exceed the force exerted by gravity.

Simply find the force of gravity (using F=m*a, where a = 9.81 m/s/s)

Any number larger than 2300N will work.4. You are trying to move a piano. The coefficient of static

friction between the carpet and the piano is 0.63. The piano weighs 405 kg. How much force is required to

accelerate the piano?

The answer is 2500N

This one is a tough oneFirst, calculate the force of friction by multiplying the force

normal by the coeff. of static frictionThe force normal is the force exerted by gravity

Since you want to move the piano, you must overcome friction, so a force larger than 2500N is necessary

5) A boy pushes on a box of mass 1 kg and it moves at an acceleration of 0.2m/s2. With what force does the boy push on the box?

POWER:

1)Frank does 2400J of work in climbing a set of stairs. If he does the work in 6 seconds, what is his power output?

2)If it takes 5 seconds for you to do 1000J of work, what is your power output?

3)A small motor does 4000J of work in 20 seconds. What is the power of the motor in watts?

4) Jan is on a crew team with three of the other Brady children. They are rowing at 22 strokes per minute. If each Brady exerts a force of 5 N while pulling an oar through a

stroke of 0.75 meters, what is the horse power provided by the Bradys?

5)Joe needs a pump that can provide 35000 Nm every hour. What power is required for this pump

WORK:

1)A 900N mountain climber scales a 100m cliff. How much work is done by the mountain climber?

2)How much work is required to pull a sled if you use 60J of work in 5 seconds?

3)Joe balances a stationary coin on the tip of his finger 20cm from the top of the table. How much work is Joe doing?

4)Amy uses 20N of force to push a lawn mower 10 meters. How much work does she do?

5)Bobby carries a 5 kg box up a two-story staircase. If each story is 5 m high, how much work did Bobby do?