Physics Answers

a circus man whose mass is 60 kg is standing on a platform 20 m above the ground while holding a trapeze which is 10 m long that is attached to the ceiling which is 26 m above the ground. the circus man swings and let go of the upswing. determine the potential energy relative to the ground if each of the following position of the circus man:

a. 20 m on the platform

b. 16 m at the bottom of the swing

c. 18 m and let's go out the trapeze

d. 9 meters halfway to the ground

A powerful motorcycle can accelerate from 0 to 36km/h in 5s. Calculate angular acceleration of its 40cm radius wheels.

Fill a 250 mL beaker with water. Get two plastic straws 12 cm long. Place one straw

in the beaker with water. Place the second straw in the position shown in the figure, and blow

hard. Ask a classmate to observe the level of water in the first straw before blowing and while

blowing into the second straw. Why does the water rise when you blow into the second straw?

2.A horizontal pipe is 2 cm in radius at one end and increases in size so that it is 5 cm in radius at

the other end. Water is pumped into the small end of the pipe at 10 m/s and a pressure of

300 kPa (kilopascal). Find the

a.) speed and

b.) pressure of the water at the pipe’s large end.

1. Calculate the pressure needed for the pump of a 3 cm radius fire hose to pump water through

its nozzle of radius 2 cm at an average speed of 4 m/s when the nozzle is 15 m above the fire

track.

6. Vector A is 3.00 units in length and points along the positive x-axis. Vector B is 4.00 units in length and points along the negative y-axis. Use graphical methods to find the magnitude and direction of the following vectors:

a. A + B

b. A - B

C. A + 2B

d. B - A

David and Karen push against the wall. David pushes with the fourth of 450 N for 60 seconds. Karen purchase with the force of 350 N for 120 seconds. How much work do they each do?

A jet aircraft is traveling at 230 m/s in horizontal flight. The engine takes in air at a rate of 96.7 kg/s and burns fuel at a rate of 3.96 kg/s. The exhaust gases are ejected at 482 m/s relative to the aircraft. Find the thrust of the jet engine. Answer in units of N.

a. M1= your mass in kg

b. M2= any body or any object and

determine the mass in kg.

C. R = 2.2 meters

I. Solve for Fg.

I. R is constant, Mjis doubled,

Mais constant, Find Fe, Will the

attraction become stronger or

weaker?

Ill. M is constant, Me is constant,

R is doubled, Solve for Fg . Will it

become weaker or stronger?

IV. M1 is constant, My is constant,

R is reduced to half. What is Fe?

Will it become stronger or

weaker?

A 400.0-N sign hangs from the end of a uniform strut. The strut is 4.0 m long and

weighs 600.0 N. The strut is supported by a hinge at the wall and by a cable whose

other end is tied to the wall at a point 3.0 m above the left end of the strut. Find the

tension in the supporting cable and the force of the hinge on the strut.