Page 69 - Physics

Introduction to force

Example 3.1 Weight of rocket on planet X, w is
X
Assume a fi xed mass rocket in Figure w = m g X
X
X
3.6, moves from the earth to a planet But, m = m
X. If it weighs 10 000 N on the earth X e
and 300 N on planet X, determine the w = m g
acceleration due to gravity on planet X. X e X
g = w X = 300 N
X m 1 000 kg
e

g = 0.3 N / kg
X
Therefore, the acceleration due to
gravity on planet X is 0.3 N/kg.

Acti vity 3.2
Aim: To measure a force
using a spring balance.

Materials needed:
Spring balance, various
objects of different
weights (e.g., small
Figure 3.6 weights, books, fruits,
etc.), table or any other
Solution hard fl at surface,
Let the weight on the earth be w .
e cushioned surface
So, the weight of the rocket on earth is Procedure
w = m g 1. Place the table or hard fl at surface at
e e e
where m is the mass of the rocket on an appropriate area for the activity.
e
earth and g is the gravitational fi eld 2. Vertically attach the spring balance
e
strength on earth which is 10 N/kg securely to the hard surface.
3. Hang an object from the spring
w
m = g e e balance, allowing the spring to
e
stretch.
10 000 N 4. Record the reading on the spring
=
10 N/kg balance.
5. Repeat steps 3 and 4 for different
m =1 000 kg
e objects.

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Physics Form 1 Final.indd 63 16/10/2024 20:56