Forces and Matter

Question 1

when held stationary ..

Answer 1

D - the spring has more elastic potential energy

Question 2

Describe the energy changes that take place until the spring stops vibrating

Answer 2

• elastic potential energy in stretched spring
• elastic potential energy transferred to kinetic energy
• change from KE to GPE
• total energy decreases
• eventually all is transferred to energy

Question 3

This device is designed to

Answer 3

B - increase the efficiency of the motorcycle

Question 4

Explain how this new type of shock absorber can provide electrical energy

Answer 4

• bump produces relative motion

- motion between the magnet and coil induces voltage

Question 5

Explain why the device will transfer more energy on road L than on road M and

Answer 5

• more frequent bumps
• bigger bumps produce bigger amplitude
• so voltage is induced

Question 6

Comment on the students conclusion

Answer 6

• the graph line is straight and passed through the origin

- and therefore conclusion is correct

Question 7

Describe the non linear stretching of the wire

Answer 7

• above 37.5N there are larger increases of extension for small increases in load

Question 8

which one of these is correct for fear wheel B

Answer 8

B

1 1/2 turns, anti-clockwise

Question 9

submarines

describe how she should determine one of the variables in this investigation

Answer 9

• determine upthrust by adding weights until the block is fully immersed
• determine weight of water by using rules to measure dimensions of the block

Question 10

Explain how pumping water into and out of the buoyancy tank affects the depth of the submarine below the surface

Answer 10

• upthrust is the force on the submarine in the water in a fluid
• upthrust on the submarine and it’s weight act in opposite directions
• upthrust is equal to the weight of water displaced by submarine
• difference in pressures on the upper and lower surfaces of the submarine causes the upthrust
• volume of the submarine is fixed so the upthrust on the submarine is constant
• increasing and decreasing volume of water in tanks increasss and decreases weight of submarine but doesn’t effect upthrust
• if weight increases to become greater than upthrust there is resultant force downwards so submarine sinks
• if weight decreases to become less than upthrust there is resultant upwards force on the submarine so it rises