Get premium membership and access questions with answers, video lessons as well as revision papers.
(i) Work done by effort = F x S = 420 N x 5.2 N = 2184 J
(ii) Load distance = 5.2 x sin25o = 2.1976
Work done by load = 900N x 2.1976 m = 1977.84 J
(iii) Efficiency = $\frac{work output}{work input}$ x 100%
Efficiency = $\frac{1977.84}{2184}$ x 100 = 90.56%
johnmulu answered the question on May 16, 2017 at 07:50
- Figure 5 shows two pulley systems being used to raise different loads. The pulleys are identical. (Solved)
Figure 5 shows two pulley systems being used to raise different loads. The pulleys are identical.
State one reason why system B may have a higher efficiency than system A.
Date posted: May 16, 2017. Answers (1)
- A body of mass 60 kg is pulled at a uniform velocity up smooth inclined surface as shown in Figure 11.(Solved)
A body of mass 60 kg is pulled at a uniform velocity up smooth inclined surface as shown in Figure 11.
If the distance moves along the incline is 4.0 m, determine work done by the force F.
Date posted: May 16, 2017. Answers (1)
- Figure 11 is a graph which shows how the vertical height through which a machine raises a mass 20 kg varies with time. (Solved)
Figure 11 is a graph which shows how the vertical height through which a machine raises a mass 20 kg varies with time.
Determine the power output of the machine after 40 seconds
Date posted: May 16, 2017. Answers (1)
- Figure 12 shows a body of weight 50N placed on a surface which is inclined at an angle of 30o to the horizontal. The body experiences a maximum frictional force of 29 N with the surface. (Solved)
Figure 12 shows a body of weight 50N placed on a surface which is inclined at an angle of 30o to the horizontal. The body experiences a maximum frictional force of 29 N with the surface.
Determine the force required to move the body, up the inclined with constant velocity
Date posted: May 16, 2017. Answers (1)
- Figure 13 shows a frictionless trolley of mass 2 kg moving with uniform velocity towards a wall.(Solved)
Figure 13 shows a frictionless trolley of mass 2 kg moving with uniform velocity towards a wall. At the front of the trolley is a spring whose spring constant is 25 Nm-1. The trolley comes to rest momentarily after compressing after compressing the spring by 3 cm and the rebounds from the wall.
(i) Determine
(I) The force exerted on the wall by the spring.
(II) The maximum acceleration of the trolley as it rebounds from the wall.
(ii) State the reason why the trolley acquires a constant velocity after it rebounds
Date posted: May 16, 2017. Answers (1)
- Figure 12 shows a lorry towing a trailer using a rope. (Solved)
Figure 12 shows a lorry towing a trailer using a rope.
The lorry exerts a force N on the trailer and the trailer exerts an equal but opposite force M on the lorry. The frictional force between the trailer and the road is F. Explain how the forces N, M and F enable the trailer to move
Date posted: May 16, 2017. Answers (1)
- Figure 5 is graph of net force on a body against its velocity as it falls through a liquid. (Solved)
Figure 5 is graph of net force on a body against its velocity as it falls through a liquid.
Determine the terminal velocity of the body.
Date posted: May 16, 2017. Answers (1)
- Two identical spherical steel balls are released from the top of two tall jars containing liquids L1 and L2 respectively. Figure 3 shows the velocity-time graph of the motion of the balls. (Solved)
Two identical spherical steel balls are released from the top of two tall jars containing liquids L1 and L2 respectively. Figure 3 shows the velocity-time graph of the motion of the balls.
Explain the nature of the curves and state why they are different.
Date posted: May 16, 2017. Answers (1)
- A ray of light incident on the surface of a glass prism is observed to behave as represented in the diagram in Fig.6(Solved)
A ray of light incident on the surface of a glass prism is observed to behave as represented in the diagram in Fig.6
Explain this observation.
Date posted: May 15, 2017. Answers (1)
- The graph in figure 10 shows the velocity of a car in the first 8 seconds as it accelerates from rest along a straight line. (Solved)
The graph in figure 10 shows the velocity of a car in the first 8 seconds as it accelerates from rest along a straight line.
Determine the distance traveled 3.0 seconds after the start.
Date posted: May 15, 2017. Answers (1)
- Figure 12 shows the path of a light ball projected horizontally. (Solved)
Figure 12 shows the path of a light ball projected horizontally.
Explain how the ball attains the new path.
Date posted: May 15, 2017. Answers (1)
- Figure 9 shows a velocity-time graph for the motion of a body of mass 2 kg. (Solved)
Figure 9 shows a velocity-time graph for the motion of a body of mass 2 kg.
Use the graph to determine the:
(i) Displacement of the body after 8 seconds
(ii) Acceleration after point B;
(iii) Force acting on the body in part (a) (ii).
Date posted: May 15, 2017. Answers (1)
- Figure 2 shows a section of a curved surface ABCD. Point A is higher than Point B while BCD is horizontal. Part ABC is smooth while CD is rough. A mass m is released from rest at A and moves towards D. (Solved)
Figure 2 shows a section of a curved surface ABCD. Point A is higher than Point B while BCD is horizontal. Part ABC is smooth while CD is rough. A mass m is released from rest at A and moves towards D.
State the changes in the velocity of m between:
(a) B and C;
(b) C and D;
Date posted: May 15, 2017. Answers (1)
- Figure 9 shows graph of velocity against time for a ball bearing released at the surface of viscous liquid. (Solved)
Figure 9 shows graph of velocity against time for a ball bearing released at the surface of viscous liquid.
Explain the motion of the ball bearing for parts.
(i) OA
(ii) AB
Date posted: May 15, 2017. Answers (1)
- Figure 3 shows a graph of velocity against time for a moving body. (Solved)
Figure 3 shows a graph of velocity against time for a moving body.
Describe the motion of the body during the 10 seconds
Date posted: May 15, 2017. Answers (1)
- Figure 9 shows a velocity-time graph for the motion of a certain body. (Solved)
Figure 9 shows a velocity-time graph for the motion of a certain body.
Describe the motion of the body in the region;
(i) OA; (ii) AB; (iii) BC;
Date posted: May 15, 2017. Answers (1)
- The graph below shows how the velocity varies with time for a body thrown vertically upwards. (Solved)
The graph below shows how the velocity varies with time for a body thrown vertically upwards.
Determine the total distance moved by the body.
Date posted: May 15, 2017. Answers (1)
- Figure 9 shows a speed-time graph for the journey of a motor car.(Solved)
Figure 9 shows a speed-time graph for the journey of a motor car.
Determine the distance the car travels in the first 40 seconds.
Date posted: May 15, 2017. Answers (1)
- Figure 5 shows air flowing through a pipe of different cross-sectional areas. Two pipes A and B are dipped into water.(Solved)
Figure 5 shows air flowing through a pipe of different cross-sectional areas. Two pipes A and B are dipped into water.
Explain the cause of the difference in the levels of water in the pipes A and B.
Date posted: May 15, 2017. Answers (1)
- Figure 5 shows a Bunsen burner. (Solved)
Figure 5 shows a Bunsen burner.
Explain how air is drawn into the burner when the gas tap is opened.
Date posted: May 15, 2017. Answers (1)