8463/1H June 2020

Coach Name: Sir Muhammad Abdullah Shah

6. Figure 9​​ shows a theme park ride called AquaShute.​​ 

Riders of the AquaShute sit on a sled and move down a slide.

i-​​ A light gate and data logger can be used to determine the speed of each rider and sled.​​ 

What two measurements are needed to determine the speed of a rider and sled?​​ 

[2 marks]

ANSWER

ii-​​ The decrease in gravitational potential energy of one rider on the slide was 8.33 kJ.​​ 

The rider moved through a vertical height of 17.0 m. gravitational field strength = 9.8 N/kg.

Calculate the mass of the rider.​​ 

[4 marks]

SOLUTION

E=mgh 

m=Egh

m=83309.8×17

m=50 kg

iii-​​ At the bottom of the slide, all riders and their sleds have approximately the same speed.​​ 

Explain why.​​ 

[4 marks]

ANSWER

According to the law of conservation of energy, total energy of the system remains the same. Therefore, decrease in gravitational potential energy is equal to increase in kinetic energy.​​ 

EK=EGrav

12mv2=mgh

gh= 12v2

v=2gh

This shows that final speed depends on gravity and height. Therefore, all riders and their sleds have approximately the same speed at the bottom of slide.​​ The minute difference in speed can be due to​​ variations in friction and resistance.​​