Forces & their EffectsEdexcel GCSE Physics: Topic test

20 questions, 54 marks

Edexcel GCSE Physics

Forces & their Effects topic test

Total 54 marks

Name

Class

Date

1
A student compares two ways of moving a small wooden block across a bench. First she pushes the block directly with her hand. Then, without touching the block again, she holds a strong magnet above it and uses it to pull the block sideways, because a thin steel plate is glued to the block's underside.
(a)
When the student pushes the block directly with her hand, what type of force is this?
[1 mark]
AA non-contact force, because forces need no touching
BA gravitational force, because gravity pulls the block
CA contact force, because the hand touches the block directly
DA magnetic force, because the block contains steel
(b)
When she instead pulls the block using the magnet held above it, not touching it, what type of force is acting?
[1 mark]
AAn electrostatic force
BA normal contact force
CA frictional force
DA magnetic force, because it acts without the objects touching
(c)
State two things this comparison shows about the difference between contact and non-contact forces, referring to both parts of the experiment.
[2 marks]
Total for question 1: 4 marks
2
A school hall door is fitted with a horizontal handle 0.8 m from its hinges. A caretaker wants to open the heavy door as easily as possible by pushing perpendicular to it.
(a)
Where should the caretaker push to open the door using the smallest possible force?
[1 mark]
AAs close to the hinge as possible
BAs far from the hinge as possible
CIt makes no difference where she pushes
DExactly halfway between the hinge and the handle
(b)
The caretaker pushes perpendicular to the door at the handle, 0.8 m from the hinge, with a force of 15 N. What moment does this produce about the hinge?
[1 mark]
A7.5 N m
B18.75 N m
C12 N m
D15.8 N m
(c)
A heavier fire door needs a force of 40 N applied 0.5 m from its hinge to just start it rotating. Calculate the moment needed to start opening the fire door, including the correct unit.
[2 marks]
Total for question 2: 4 marks
3
A tugboat tows a barge across a canal using a rope. The tugboat's engine produces a driving force of 3000 N forward on the barge through the rope, while water resistance acts on the barge with a force of 1800 N backward as it moves.
(a)
Calculate the resultant horizontal force on the barge while it is being towed, and state its direction.
[3 marks]
(b)
Explain, using the idea of resultant force, what happens to the barge's motion while the resultant force found in part (a) continues to act, and describe how its motion would change if the water resistance later increased until it exactly equalled the driving force.
[4 marks]
Total for question 3: 7 marks
4
A carpenter uses the claw of a hammer as a lever to pull a bent nail from a thick wooden beam. The claw rests against the beam and acts as the pivot. She pushes down on the end of the handle, 0.35 m from the pivot, with a force of 60 N, while the nail resists being pulled with a force acting 0.05 m from the pivot.
(a)
Calculate the force exerted on the nail, assuming the hammer is balanced about the pivot, and explain, using the idea of moments, why using a hammer with a longer handle would make removing a stiff nail easier.
[6 marks]
(b)
Once the nail is out, the carpenter holds the same hammer horizontally, gripping only the handle so her hand acts as a pivot. She applies an upward force with her fingers near the head end and a downward force with her thumb near the far end of the handle, keeping the hammer stationary and horizontal. Explain how the hammer can stay in equilibrium under these two forces even though they act at different places, referring to both linear equilibrium (resultant force) and rotational equilibrium (moments).
[6 marks]
Total for question 4: 12 marks
5
A skydiver of weight 800 N jumps from a stationary hot air balloon. Before she opens her parachute, gravity pulls her downward. After she opens the parachute, the canopy also experiences an upward drag force caused by air particles colliding with the fabric as she falls.
(a)
What type of force is the gravitational pull acting on the skydiver before she opens her parachute?
[1 mark]
AA non-contact force
BA contact force
CA frictional force
DA normal contact force
(b)
What type of force is the drag from air particles colliding with the parachute canopy after it opens?
[1 mark]
AA non-contact force
BA gravitational force
CA magnetic force
DA contact force
(c)
Once the parachute is fully open, the skydiver falls at a constant velocity. State what this tells you about the resultant force acting on her at this point, and explain why, in terms of the two forces described above.
[2 marks]
Total for question 5: 4 marks
6
A pair of scissors is used to cut thick cardboard. The rivet joining the two blades acts as the pivot. A craft teacher applies a force of 24 N to the handle, 0.09 m from the pivot, while the cardboard resists cutting at a point on the blade 0.03 m from the pivot.
(a)
Compared with cutting thin paper near the tip of the blades, why is it easier to cut thick cardboard using the part of the blades closest to the pivot?
[1 mark]
ABecause the blades are sharper closer to the pivot
BBecause the distance from the pivot to the cardboard is smaller there, so a larger force is produced for the same handle moment
CBecause the handle force is larger when cutting near the pivot
DBecause friction between the blades is lower closer to the pivot
(b)
The teacher applies 24 N to the handle, 0.09 m from the pivot. What moment does this produce about the pivot?
[1 mark]
A2.16 N m
B21.6 N m
C24.09 N m
D0.216 N m
(c)
Assuming the scissors are balanced about the pivot while cutting, calculate the force the blade exerts on the cardboard at a point 0.03 m from the pivot, using the moment found in part (b).
[2 marks]
Total for question 6: 4 marks
7
A shop sign of weight 150 N hangs in equilibrium, supported by two vertical cables. One cable provides an upward force of 90 N and the other provides an upward force of 60 N, with no horizontal forces acting.
(a)
Show that the sign is in vertical equilibrium, and state what this confirms about the resultant force acting on it.
[3 marks]
(b)
The cable providing 90 N snaps completely, leaving only the cable providing 60 N supporting the sign. Explain, using Newton's first and second laws, what happens to the sign immediately after the cable snaps.
[4 marks]
Total for question 7: 7 marks
8
A mechanic raises one corner of a car using a hydraulic jack until that wheel is off the ground, then slides a solid axle stand under the chassis and slowly lowers the jack so the car's weight rests on the stand instead. To loosen the wheel nuts, she fits a long-handled breaker bar to each nut and applies a force perpendicular to the bar, 0.4 m from the nut.
(a)
One wheel nut needs a moment of 180 N m to loosen it. Calculate the minimum force the mechanic must apply perpendicular to the breaker bar, 0.4 m from the nut, to loosen it, and explain why a mechanic would choose a longer breaker bar rather than a shorter one for a very tight nut.
[6 marks]
(b)
While only the jack supports that corner, the car's weight there (3000 N) is balanced entirely by the upward force from the jack. Explain what happens to the forces supporting that corner as the jack is slowly lowered until the axle stand takes over, referring to resultant force and equilibrium, and explain one safety reason why mechanics are trained to always transfer the car's weight onto a solid stand rather than leaving it supported only by the jack.
[6 marks]
Total for question 8: 12 marks

End of questions