Question

1. Khalif runs a full lap around a circular track of radius 20 m in 100 s. What is the
magnitude of his average velocity?

2. A 10 Newton force is needed to move an object with a constant velocity of 5.0 m/s.
What power must be delivered to the object by the force?

3. A ball is kicked horizontally with an initial speed of 8.0 m/s from the edge of a cliff. A stop watch measures the ball’s trajectory time from top of cliff to bottom to be 3.4 s. What is the height of the cliff AND range of the ball?

4. A 10 Newton force is needed to move an object with a constant velocity of 5.0 m/s. What power must be delivered to the object by the force?

5. An object weighs 100 N on the surface of Earth. What is the mass of this object on the
surface of the Moon where the acceleration due to gravity is 1.7 ms^−2?

Answer 1

(a) average velocity (actually there should be average speed ) is gien by

• 
• 
• ............................(Answer)

(b) given that F = 10 N , v= 5 m/s

so the power delivered to the object will be

• 
• 
• ......................(Answer)

(c) here given that initial speed u = 8 m/s , time of flight = 2 time to reach from top to bottom = 6.8 s

maximum height = H = ? , Range =?

• 
• 
• m ...............................(answer)
• R = u T
• R= 8 3.4
• m ................(answer)

(d) given that F = 10 N , v= 5 m/s

P = Fv

• 
• watt,,,,,,,,,,,,,,,,,(answer)

(e) weight on the earth = W = mg = 100

mass =

• 
• 
• 
• now the mass is not changed on the earth or moon so on the moon the mass will be same .