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Grade 8 Science SA 1 (Criterion A)

Last updated over 5 years ago

12 questions

Note from the author:

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Grade 8 Science SA 1 (Criterion A)

Question 1

1.

A kettle uses 1200J of electrical energy.
900J of thermal energy is used to heat water, 300J of thermal energy is wasted and lost to the surroundings.
Draw a sankey diagram to represent the energy transfer.
How many joules does each square represent?
Calculate the efficiency of the kettle. Show your working.

Question 2

2.

A box with a weight of 650 N is sitting on the ground and the bottom of the box measures 0.5 m by 0.7 m. What is the pressure exerted by the box on the ground?

Question 3

3.

A pressure of 20 Pa is applied by an 8‎ ‎000 N force to a square area. What is the length of a side of the square?

Question 4

4.

How much work is done on a small car if a 3150 N force is exerted to move it 75.5 m to the side of the road?

Question 5

5.

If a person does 6000 Joules of work in one minute, what power has he?

Question 6

6.

A clown is performing with his feet on the circus ground. Which of the following activities increases the pressure of the clown on the circus ground?

When the clown rotates around himself

When the clown bows slowly

When the clown stands on one foot

When the clown claps his hands

Question 7

7.

Two identical cubes are placed on top of each other. If the top cube is removed from above the other and placed next to it, the pressure due to the cubes on the surface underneath them will __________.

remain constant

be indeterminable

decrease to the half

increase to the double

Question 8

8.

What class lever are tongs?

1st

2nd

3rd

Question 9

9.

What class lever is a stapler?

1st

2nd

3rd

Question 10

10.

A boy of weight 600N sits on the see-saw as shown at a distance of 1.5m from the pivot. What is the force F required at the other end to balance the see-saw?

450 N

350 N

4.5 N

200N

Question 11

11.

What is the moment produced by the 15 N?

1.5 Nm (anti - clockwise)

15 Nm (clockwise)

150 Nm (anti - clockwise)

0.15 Nm (clockwise)

Question 12

12.

A seesaw is unbalanced with two people of different masses sitting equal distances from the center. Which of the following will result in equilibrium?

The larger person moving further away from the center.

Moving the smaller person closer to the center.

Moving the smaller person further from the center.

Making the larger person do nothing.