10 minutes maximum! (can you do it in 5?)
For all these questions you may take g = 10 ms^{2}.
13. A bowling ball of mass 6 kg rolls down a frictionless slope as shown here:


1. What is the gravitational potential energy of the ball at the top of the slope?
 A. 18 J
 B. 300 J^{}
 C. 180 J^{}
 D. 30 J


2. What is the kinetic energy of the ball at the bottom of the slope?
 A. 18 J
 B. 300 J^{}
 C. 180 J^{}
 D. 30 J


3. What is the impact velocity of the ball?
 A. √6 ms^{1}
 B. √60 ms^{1}
 C. √30 ms^{1}
 D. 60 ms^{1}


4. A 2 kg brick is held 1.5 m above the ground, and then thrown horizontally at 5 ms^{1}. Which of these gives the potential and kinetic energy of the brick just after being thrown?

Kinetic Energy (J) 
Gravitational Potential Energy (J) 
A 
5 
3 
B 
25 
3 
C 
25 
30 
D 
50 
30 


5 & 6. An old light bulb is rated as having a 50 W input. It is left on for 5 minutes. 


5. How much electrical energy is supplied to the bulb over this time?
 A. 15 kJ
 B. 3 kJ
 C. 250 J^{}
 D. 600 J


6. What is the visible light output of the bulb if it is 20 % efficient?
 A. 10 W
 B. 5 W^{}
 C. 25 W^{}
 D. 250 W


7. A steel cable is used in a suspension bridge.
The cable is stretched by a distance x, storing E joules of elastic energy. 

What is the energy stored if the cable extension increases to 4x ?
 A. 2 E
 B. 4 E^{}
 C. 8 E^{}
 D. 16 E


8. A climbing rope is stretched, and the force and extension recorded. The rope produces a forceextension graph like this:


The energy stored in the rope when it has an extension of x is:
 A. The area under the line
 B. The gradient of the line at x.^{}
 C. F.x ^{}
 D. ½ F.x


9&10. A large concrete block is dragged 10 m along rough ground by a force of 800 N. The force acts at an angle as shown in the diagram.


9. The work done  in joules  in moving a distance of 10 m along the ground is:
 A. 800 cos θ
 B. 8000 cos θ
 C. 800 sin θ
 D. 8000 sin θ


10. If the block is pulled at a velocity of 2 ms^{1}, the power working against friction, measured in watts, is:
 A. 1600
 B. 16000
 C. 1600 ^{}cos θ
 D. 16000 cos θ


