Units (Forces and Motion)
3 marks · HardA laboratory uses special scales that output mass readings in grams (g). An object on such a scale measures 6350 g.
Convert this mass into kilograms, giving the correct unit and symbol.
If the object exerts a weight of exactly 62.3 N on the scales, calculate the local gravitational field strength in N/kg (give your answer to 2 decimal places, including the correct unit and symbol).
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) 6.35 kg · must show kg
(b) 9.82 N/kg · must show N/kg
Must show: kg, N/kg
Common mistakes: leaving mass in g; omitting units
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Converts 6350 g to 6.35 kg; includes correct unit and symbol.
M1 (b) · 1 mark · Uses correct formula for g = weight/mass with values substituted.
A1 (b) · 1 mark · Final answer correct to 2 decimal places, correct unit and symbol (N/kg).
Worked solution
a) 6350 g = 6350/1000 = 6.35 kg
b) Gravitational field strength g = weight/mass = 62.3 N / 6.35 kg = 9.811.... = 9.82 N/kg (2 d.p.)