Download Formative 1

Physics unit 2 Formative 1 - V1
Name: __________________________
Date: __________________
Answer the questions in the space provided.
1. Define the term ‘Force’.
(2 K)
Force is a push or pull upon an object resulting from the object's interaction with another
object. Force changes the state of motion of an object. It is measured in Newtons.
Force is the product of mass and acceleration. It is measured in Newtons.
2. Give two real life examples to explain Newton’s third law of motion.
(2 A)
Rocket launch: downward thrust causes the rocket to move upwards.
Swimming: Water pushed back to move forward
3. Ethan is dragging a bag of grass from the garage to the street on the evening before
garbage pick-up day. The diagram at the right is a free-body diagram. It uses arrows to
represent the forces acting upon the bag.
a. Each force is labeled according to type. The magnitude of the force is
represented by the size of the arrow. Use the free body diagram to determine the net
force acting upon the bag. The values of the individual forces are:
(1 A)
Fgrav = Fnorm = 60.5 N Fapp = 40.2 N
Ffrict = 5.7 N.
Fnet = 40.2 – 5.7 = 34.5 N
b. Use the net force calculated above to determine the acceleration of this bag if its
mass is about 6 kg.
(2 A)
F = ma, therefore
a = F/m = 34.5/6 = 5.75 m/s2
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Physics unit 2 Formative 1 - V1
4. Define the term ‘Work’.
(1 K)
Work is the product of force and distance moved by an object in a direction parallel
to the force.
5. If a wooden block is dragged for equal distances on a smooth surface first and then on a
rough surface. Would the amount of work done be equal? Explain.
(2 A)
The amount of work done will not be equal because the rought surface will have more
friction and therefore would require more force to cover the same distance. Thus,
more work will be done in dragging the block on the rough surface.
6.
Determine the net force required to accelerate a 540-kg car from 0 to 27 m/s in 10.0
seconds.
(2 A)
a v – u = 27 – 0 = 2.7 m/s2
t
10
=
F = ma = 540 x 2.7 = 1458 N
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