Practical Skills I : Planning

A student investigated the acceleration of a trolley as it rolled down a ramp. The trolley was released from rest at the top of the ramp and allowed to roll onto a horizontal surface. There was a single light gate above the horizontal surface, as shown.

Describe how the student could determine the velocity v of the trolley as it passed through the light gate.

(3)

Mean v = ............................ m s^–1
Percentage uncertainty in v =........................... %

Determine the acceleration of the trolley on the ramp.

s = 1.50 m

(2)

Acceleration = ............................. m s^–2

State why this does not show that the results are reproducible.

(1)

A student was asked to investigate the ultimate tensile stress of a sample of thin nylon fishing line.

Before testing, the student measured the diameter at five points along the sample of nylon fishing line.

            0.55mm        0.57mm       0.54mm      0.55mm       0.53mm

(3)

Percentage uncertainty = .........................................

(5)

The specific latent heat of vaporisation L of water can be determined using the apparatus shown.

One significant source of error in this experiment is the uncertainty in the mass reading due to the water moving as it boils.
Explain how another significant source of error affects the value of L.