CIE iGCSE Co-Ordinated Science P1.5.2 Turning effect of forces Exam Style Questions Paper 1
Question
The diagram shows a metre rule with a pivot at the 60 cm mark. A force of 6.0 N is applied at the
35 cm mark in the direction shown.
What is the moment of the 6.0 N force about the pivot?
A 150 Ncm B 210 Ncm C 360 Ncm D 390 Ncm
▶️Answer/Explanation
Ans :A
Question
A uniform plank is placed on a pivot, with its centre immediately above the pivot. A load of 10 N is suspended on the left, 45 cm from the pivot, and a load of 20 N is suspended on the right, 45 cm from the pivot.
What happens to the plank?
A The left-hand side moves down, the right-hand side moves up and the plank does not return
to its horizontal position.
B The left-hand side moves up, the right-hand side moves down and the plank does not return
to its horizontal position.
C The plank moves down on one side then returns to its horizontal position.
D The plank remains horizontal without moving.
▶️Answer/Explanation
Ans : B
Question
A force of 10 N is applied to a beam at a distance of 0.25 m from a pivot.
Which calculation gives the moment of the force about the pivot in N m?
(A) 10 × 0.25
(B) $\frac{10}{0.25}$
(C) 10 + 0.25
(D) 10 – 0.25
▶️Answer/Explanation
Ans : A
Question
What is a suitable unit for the moment of a force?
A Nkg B N/ kg C N m D N/ m
▶️Answer/Explanation
Ans : C
Question
A boy pulls a nail from a block of wood using a hammer, as shown.
The boy pulls the hammer with a force of 15 N in the position shown.
What is the moment produced about the pivot by the boy pulling on the hammer?
A 0.90 N m B 2.4 N m C 3.3 N m D 4.2 N m
▶️Answer/Explanation
Ans : C
Question
The diagram shows a triangular sheet of metal with sides of length 50 cm, 40 cm and 30 cm. The
sheet is free to move about a pivot at the top corner, as shown.
A cord is attached to the bottom left corner of the sheet and pulled with a horizontal force of 5.0 N
to the left.
What is the moment of the 5.0 N force about the pivot?
(A) 150Ncm (B) 200Ncm (C) 250Ncm (D) 600Ncm
▶️Answer/Explanation
Ans : B
Question
The diagram shows a child of weight 240 N sitting on a see-saw (teeter-totter) at a distance of 1.6 m from the pivot.
What is the moment of the weight of the child about the pivot, with the correct unit?
(A) 150 N m
(B) 150 N/ m
(C) 384 N m
(D) 384 N/ m
▶️Answer/Explanation
Ans : C
Question
A scientist uses a lever to lift a heavy load.
She applies a force of 120 N at a distance of 360 cm from a pivot.
What is the moment about the pivot of the force applied by the scientist?
A 3.0 N m
B 33.3 N m
C 432 N m
D 43 200 N m
▶️Answer/Explanation
Answer: C 432 N m
Explanation: The moment (torque) is calculated using the formula: moment = force × distance. Here, the distance must be in meters, so 360 cm = 3.6 m. Thus, moment = 120 N × 3.6 m = 432 N m.
Question
What is meant by the moment of a force?
A) the speed of an object moved by a force
B) the time taken for a force to move an object
C) the turning effect of a force
D) the work done by a force
▶️Answer/Explanation
Answer: C) the turning effect of a force
Explanation: The moment of a force is the turning effect of the force, calculated as the product of the force and the perpendicular distance from the pivot point.