Page 68 - CITS - WCS - Mechanical

WORKSHOP SCIENCE - CITS

Fig 9

Assignment

Ex: 1.

Amit has a cycle mass of 50 kg. How much force should he apply to the cycle so that it should travel with the
acceleration of 10 m/s2?
Solution:

Known,
• M (Mass of toy car) = 50 Kg,
• A (Acceleration) = 10 m/s2,
F is Force to be applied : = M × A
= 50Kg × 10 m/s2 = 500 Kg m/s2 = 500 N.

Solved Problems
Ex.2. Virat uses 30N of power to push a 2kg box to the left. Rahul uses 40N of force to push the same box to the
right. What is the box’s net force?

Possible responses:
a 1.33N
b 10N
c −10N
d 0.75N

Ans. We sum together all the forces to get the net force:
Fnet=Fvirat+FRahul Fnet=Fvirat+FRahul
Since force is a vector, the direction of action is important. We shall turn leftward motion into a negative and
rightward motion into a positive. Virat is pushing to the left with 30N 30N
hence his force is30N 30N. Rahul was pushing to the right with 40N40N
thus his force will stay 40N.
We can get the net force by summing the individual force together.
Fnet=−30N+40NFnet=−30N+40N

Fnet=10N
Ex. 3. A constant force acting on a body of mass 3.0 kg changes its speed from 2.0 m/s to 3.5m/s in 25 s. The
direction of the motion of the body does not changes. What is the magnitude and what is the direction of the
force?

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CITS : WCS - Mechanical - Exercise 4 CITS : WCS - Mechanical - Exercise 4