Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Forces and Motion
367 practice questions
Topics covered
Practice questions
341–350 of 367
Question 341
6 marks · Hard
Answer and see the solution →A uniform metal plank of length 2.5 m and mass 4.0 kg is placed horizontally across a small stream, resting on rocks at each end (points R and S). A stone of mass 2.0 kg is placed 0.75 m from end R, as shown.
Plank and stone over stream Take gravitational field strength . Ignore the weight of the plank unless stated otherwise.
(a)[3 marks]Calculate the upward force at support S when only the stone is on the plank. (Ignore the weight of the plank.)
(b)[3 marks]Now include the weight of the plank. Calculate the new upward force at support S.
Question 342
5 marks · Hard
Answer and see the solution →A carpenter tries to lift a heavy lid off a crate using a crowbar. The crowbar is 1.2 m long. She places the fulcrum (pivot point) 0.2 m from one end. She applies a vertical downward force of 250 N at the far end of the bar (opposite the pivot).
(a)[2 marks]Calculate the moment produced by the carpenter's force about the fulcrum.
(b)[3 marks]If the lid is just lifted (i.e., the system is in balance), calculate the minimum upward force at the lid end needed to balance the moment.
Question 343
5 marks · Hard
Answer and see the solution →An athlete is balancing on a horizontal board that is supported at both ends (points L and M). The board has negligible mass. The athlete stands a distance d from support L on the 3.0 m long board. The athlete's weight is 630 N.
(a)[2 marks]Write an expression for the upward force, F_M, at support M in terms of d.
(b)[3 marks]The athlete stands 2.2 m from support L. Calculate the upward force at support M.
Question 344
4 marks · Easy
Answer and see the solution →A car slows from 20 m/s to rest in 4 s when the brakes are applied. The car has a mass of 1000 kg.
(a)[2 marks]Calculate the acceleration of the car while braking.
(b)[2 marks]Calculate the braking force applied to the car.
Question 345
4 marks · Easy
Answer and see the solution →A block is pulled along a rough, horizontal surface. The block experiences a friction force and is stretched by a spring attached to it.
(a)[1 mark]Describe one effect of the friction force on the block as it moves along the surface.
(b)[2 marks]The spring attached to the block is stretched. State what will happen to the shape of the spring when the block is released and explain your answer.
(c)[1 mark]Name the type of force that causes the spring to return to its original shape.
Question 346
4 marks · Easy
Answer and see the solution →A trolley of mass 0.80 kg is pushed by a constant force of 2.0 N along a smooth, straight track.
(a)[2 marks]Calculate the acceleration of the trolley.
(b)[1 mark]Is the acceleration a vector or a scalar quantity? Explain your answer.
(c)[1 mark]State the unit for force.
Question 347
4 marks · Easy
Answer and see the solution →A student pushes a wooden block of mass 0.5 kg along a table. There is a force due to friction acting between the block and the table. The block is attached to a spring and a ruler is used to measure the extension of the spring as it moves.
(a)[1 mark]State one effect of friction on the motion of the block.
(b)[2 marks]The table below shows the force measured by the spring and the extension of the spring for different trials.
Force (N) Extension (cm) 0.0 0.0 1.0 1.4 2.0 2.8 3.0 4.2 State whether this spring obeys Hooke’s law in these trials. Give a reason for your answer.
(c)[1 mark]Describe what will happen to the extension of the spring if a larger force is applied and the spring is stretched beyond its elastic limit.
Question 348
4 marks · Easy
Answer and see the solution →A student is riding a bicycle. While pedalling, the student applies a forward force of 50 N. The friction and air resistance together produce a resisting force of 20 N.
(a)[1 mark]Calculate the resultant force acting on the bicycle.
(b)[2 marks]The mass of the bicycle and the student is 70 kg. Calculate the acceleration of the bicycle.
(c)[1 mark]Describe one way the student could increase the bicycle's acceleration without changing their mass.
Question 349
6 marks · Normal
Answer and see the solution →A 2.0 m long uniform beam of mass 8.0 kg is supported at each end. A box of mass 12 kg is placed 1.2 m from one end of the beam.
(a)[2 marks]Calculate the weight of the beam and the weight of the box. Give your answers in newtons (N). (Take .)
(b)[1 mark]Find the total downward force acting on the supports.
(c)[3 marks]Calculate the upward force on the support that is closest to the box. Show your working.
Question 350
5 marks · Normal
Answer and see the solution →A spring has an unstretched length of 7.0 cm. The table below shows how the length of the spring changes as different forces are applied.
Force and length data for a spring Force (N) Length (cm) 0 7.0 2 7.5 4 8.1 6 8.7 8 9.2 (a)[1 mark]Complete the following column to show the extension of the spring for each force.
Force (N) Extension (cm) 0 2 4 6 8 (b)[2 marks]Plot a graph of force (y-axis) against extension (x-axis). (Describe the shape of the graph.)
(c)[2 marks]Does this spring obey Hooke’s law over the range of forces shown? Explain your answer.