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.
2 points
2
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?
2 points
2
Question 3
3.
A pressure of 20 Pa is applied by an 8âââ000 N force to a square area. What is the length of a side of the square?
2 points
2
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?
2 points
2
Question 5
5.
If a person does 6000 Joules of work in one minute, what power has he?
1 point
1
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?
1 point
1
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 __________.
1 point
1
Question 8
8.
What class lever are tongs?
1 point
1
Question 9
9.
What class lever is a stapler?
1 point
1
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?
1 point
1
Question 11
11.
What is the moment produced by the 15 N?
1 point
1
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?