Question 7
Which statement
includes a correct unit?
A energy
= 7.8 N s
B force
= 3.8 N s
C momentum
= 6.2 N s
D torque = 4.7 N s
Reference: Past Exam Paper – June 2015 Paper 13 Q1
Solution:
Answer:
C.
The unit Ns indicates the product
of the quantity having unit N and quantity having unit s. That is, force × time.
Energy is force ×
distance. [A is incorrect]
The unit of force is N, so
N s is an incorrect unit for force. [B is incorrect]
Force = Δp / t
Δp = F × t
So, momentum can have unit
N × s. [C is correct]
Torque = Force × distance
So, unit of torque: N m, not N s. [D is incorrect]
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