Test 4-1

Test 4
1 (a) State the equation relating efficiency to mechanical advantage and velocity ratio. [1]
(b) A block and tackle system of 5 pulleys is used to raise a load of 500 N steadily through a
height of 20 m. The work done against friction is 200 J.
Calculate the
(i) work done in raising the load, [1]
(ii) work done by the effort [1]
(iii) efficiency of the system. [2]
[Total: 6]
2 A girl lifts a bucket full of water from a well at a steady speed, using a pulley as shown in
Figure 2.1.
Figure 2.1
The mass of the bucket and the water is 15 kg. The force, F, applied by the girl is 160 N.
(a) Determine the weight of the bucket and water given that g = 10 N/kg. [2]
(b) The bucket is raised through a height of 6 m.
(i) State the type of energy gained by the bucket. [1]
(b) (ii) Calculate the work done by the girl. [2]
[Total: 5]
3 (a) State Newton’s third Law of Motion. [1]
(b) Figure 3.1 shows a uniform bar of length 10 m in equilibrium.
Figure 3.1
Calculate the
(i) weight, W, of the bar. [2]
(ii) force, Y, which the pivot exerts on the bar. [1]
[Total: 4]
4 A girl of mass 35 kg, on a bicycle, accelerates from rest and travels down a slope in a
straight line.
The girl does not use the pedals.
Figure 4.1 shows that the gradient of the slope is constant.

Figure 4.1
(a) Calculate the resultant force on the girl when she is accelerating at 2.6 m / s2. [2]
(b) At first, her acceleration is constant. At time t1, her acceleration starts to decrease
gradually until she is travelling at a constant speed in a straight line.
(i) On Figure 4.2, sketch a speed-time graph for the girl from when she starts moving until
she is travelling at a constant speed. [2]
Figure 4.2
(ii) State how the distance travelled is found from a speed-time graph. [1]
[Total: 5]
5 A small crack appears in an oil tank and a stream of oil is pushed out through the crack.
The oil hits the floor at P where a puddle of oil starts to form.
Figure 5.1 shows the oil tank.

Figure 5.1
The gravitational field strength g is equal to 10 N / kg.
(a) The density of the oil is 940 kg / m3 and the crack is 3.3 m below the surface of the oil.
(i) Calculate the pressure due to the oil at the level of the crack. [2]
(ii) Explain why the atmospheric pressure does not affect the rate at which the oil is pushed
out through the crack. [1]
(b) As time passes, the point where the oil hits the floor moves away from P and towards the
tank.
Explain why this happens. [2]
[Total: 5]
8 A bucket of water is pulled up out of a well using a rope. Figure 6.1 shows the rope
winding on to a cylinder as the handle is turned.
Figure 6.1
The empty bucket has a mass of 1.0 kg.
(a) Complete the sentences that describe mass by filling in the gaps.
The mass of a body is a measure of the amount of ................................................................. in

the body. It resists a change in the state of ................................................................. of the
body. [2]
(b) When the bucket is full, it contains 2.4 × 10–2 m3 of water.
The gravitational field strength g is equal to 10 N / kg.
(i) Explain what is meant by a gravitational field. [1]
(ii) The density of water is 1000 kg / m3.
Determine the total weight of the bucket and the water. [3]
(c) The radius of the cylinder is 0.12 m and the handle is 0.40 m from the axle of the cylinder.
The weight of the bucket and the water produce a moment that acts on the cylinder.
(i) Calculate this moment. [2]

(ii) Calculate the minimum force on the handle that balances this moment. [1]
(d) A farmer pulls the bucket of water up at a constant speed. He needs to exert a force on the
handle that is greater than that calculated in (c)(ii). He notices that there is a slight increase in
temperature where the axle is in contact with the frame holding it.
(i) Suggest two reasons why the force exerted is greater than the value calculated. [2]
(ii) State the energy changes that are taking place as the bucket is being lifted at a constant
speed. [3]
(e) State what can be deduced about the forces acting on the bucket when it is travelling
upwards at a constant speed. [1]
[Total: 15]
[Total: 40]

Test 4-1

Uploaded by

Copyright:

Available Formats

Test 4-1

Uploaded by

Document Information

Original Description:

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Test 4-1

Uploaded by

Copyright:

Available Formats

Test 4

(i) work done in raising the load, [1]

(ii) work done by the effort [1]

(iii) efficiency of the system. [2]

(b) The bucket is raised through a height of 6 m.

(i) State the type of energy gained by the bucket. [1]

(b) (ii) Calculate the work done by the girl. [2]

3 (a) State Newton’s third Law of Motion. [1]

(b) Figure 3.1 shows a uniform bar of length 10 m in equilibrium.

(i) weight, W, of the bar. [2]

(ii) force, Y, which the pivot exerts on the bar. [1]

The girl does not use the pedals.

Figure 4.1 shows that the gradient of the slope is constant.

Figure 5.1 shows the oil tank.

The gravitational field strength g is equal to 10 N / kg.

Explain why this happens. [2]

The empty bucket has a mass of 1.0 kg.

The mass of a body is a measure of the amount of ................................................................. in

(b) When the bucket is full, it contains 2.4 × 10–2 m3 of water.

The gravitational field strength g is equal to 10 N / kg.

(i) Explain what is meant by a gravitational field. [1]

(ii) The density of water is 1000 kg / m3.

(i) Calculate this moment. [2]

You might also like