CIE iGCSE Co-Ordinated Science P1.5.3 Centre of gravity Exam Style Questions Paper 1
Question
Three objects X, Y, and Z are at rest on a table. The centre of mass of each object is labelled M.
What is the order of stability of these three objects, from most stable to least stable?
A. X → Y → Z
B. Y → Z → X
C. X → Z → Y
D. Z → Y → X
▶️Answer/Explanation
Answer: D
Explanation: The stability of an object depends on the position of its centre of mass. The lower the centre of mass, the more stable the object. Therefore, Z (lowest centre of mass) is the most stable, followed by Y, and then X (least stable).
Question
A student wishes to determine the centre of mass of a piece of card.
She makes five holes in the card.
She suspends the card from a pin, as shown.
She hangs a load from a thread attached to the pin and marks the line of the thread on the card.
The student repeats the procedure using a different hole. What is the smallest number of lines that she needs to draw to determine the position of the centre of mass of the card?
A. 1
B. 2
C. 3
D. 4
▶️Answer/Explanation
Answer: B. 2
Explanation: The centre of mass is the point where the lines intersect. Drawing two lines from different suspension points is sufficient to determine the intersection point.
Question
A parachutist and his parachute have a combined weight W. The parachutist falls vertically towards the Earth’s surface. The force of air resistance R opposes his motion.
The speed of the parachutist is constant.
Which statement about the forces on the parachutist is correct?
A W and R are both equal to zero.
B W is equal to R and greater than zero.
C W is greater than R.
D W is less than R.
▶️Answer/Explanation
Ans : B