2. WHAT IS RESULTANT FORCE?
The resultant force is the difference between the two forces acting in
opposite directions on an object. The resultant force is zero if both forces
are equal. The object is accelerating if the resultant force is not zero.
For Example:
100N-50N=50N
Resultant Force
=50N
Direction of travel
50N100N
3. FORCE, MASS & ACCELERATION.
What factors affect an accelerating object? (Remember that objects accelerate
when their resultant force is not zero)
The Mass of the object: Objects with a small mass will accelerate more than
objects with a large mass.
The size of the force:The larger the resultant force acting on the object, the larger
the acceleration.
Calculation:
a=F/m or F= m x a or m=F/a
a=Acceleration of the object (Metres per Second squared, m/s^2)
F=Resultant force (Newtons, N)
m=Mass of the object (Kilograms, kg)
4. CALCULATION QUESTIONS:
1. A football weighs 0.5kg and is kicked so that it accelerates at 50 m/s^2.How
much force is acting on the ball?
2. The wind puches a paper cup which weighs 50g along the beach.The cup is
accelerating at 5 m/s^2. How much force is acting on the cup?
3. A block weighs 5kg and has a force of 20N acting on it.What is it's acceleration?
4. If an object has a force of 270N acting on it and it's accelerating at 9 m/s^2,
what is the object's mass?
5. ANSWERS:
1) 25N
F= a x m
F= 50 x 0.5
F= 25
2) 0.05N
50g/1000 = 0.05kg
F= a x m
F= 5 x 0.05
F= 0.25
3) 4 m/s^2
• a = F/m
• a= 20/5
• a= 4
