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Physics

ACT A barrel is filled with water. Kaisar removed exactly half the water DID YOU KNOW?
from the barrel, using a bucket, and the remaining water was removed
by Marat. Did Kaisar and Marat do the same amount of work? What The human brain consumes
can be said about their power if they took the same amount of time to about 25 watts of energy
complete their tasks? during waking hours. This
amount of energy is enough
INV Investigate the power of an electric motor lifting a load to a certain to power a small bulb.
obtained. textbooks nis edu kz
height, recording the time at each step. So where do we take this
energy from?

light
energy
electrical energy 100 J 25 J

thermal energy 25 J

1. Does the power of the engine depend on the height it is lifting to?
What about time spent?

2. Write the results of your measurements and calculations in a table.
Using the data you obtained, plot a work done vs. time spent graph.

3. Make a conclusion about the factors affecting the power.

EXT What effect does increasing the engine’s power have on the
process in general?

OVER TO YOU!

The link between a car engine’s motive 70 000
force and the car’s speed was studied.
60 000
A graph was plotted using the data
Motive force, N 50 000

a) Determine the power of the engine 40 000
for each speed shown. 30 000

b) Determine the total work done by 20 000
the engine assuming the data were 10 000
recorded every 10 seconds.
0
1.5 4 7 12.5 20
c) Explain the results. Speed, m/s

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