Physics 2018

Question 1

When the ball hits the ground, energy is transferred from the ball to the Earth.
Explain how the data in Figure 1 shows this energy transfer.

Answer 1

velocity just after bounce is less than just before bounce
or
the height at the top of the bounce is less than the height from which it was dropped
so the ball has lost energy
correct reference to (loss of) ke or (reduced) gpe
total energy of ball and Earth / ground is constant

Question 2

Extension of a spring practical and sources of inaccuracies

Answer 2

set up a clamp stand with a clamp hang the spring from the clamp
use a second clamp and boss to fix a (half) metre ruler alongside the spring
record the metre ruler reading that is level with the bottom of the spring
hang a 2 N weight from the bottom of the spring record the new position of the bottom of the spring calculate the extension of the spring
measure the extension of the spring
add further weights to the spring so the force increases 2 N at a time up to 10 N
for each new force record the position of the bottom of the spring and calculate / measure the extension
possible source of inaccuracy
not fixing the ruler in position but simply holding the ruler next to the spring
not clamping the ruler vertical
misjudging the position of the bottom of the spring
parallax error
allow any other sensible suggestion that could reasonably lead to inaccuracy in the data
allow a description that would increase accuracy repeating the measurements is insufficient

Question 3

How does the data support hookes law

Answer 3

Straight line that passes through origin on the graph

Question 4

What is accurate data

Answer 4

Predicted data is close to accurate values

Question 5

Why was it important that uranium was found

Answer 5

supported the prediction (made by Bode)
so provides evidence that the equation is true / correct / works / accurate

Question 6

How does a graph show that a step up transformer has become a step down

Answer 6

The pd has increased to above 2