Answer:
Friction: When two surfaces slide against each other / make contact with each other
Force: A push or pull exerted on an object
Answer:
1
Explanation:
it go up than down than up
Work is done when a force is in the same direction as the object moves.
Explanation:
The work done by a force in moving an object is given by the equation

where
F is the magnitude of the force
d is the displacement of the object
is the angle between the directions of F and d
From the equation, we notice the following:
- Work is done by a force when the force is in the same direction as the object moves. In fact, in this case,
, and so
, which means that the work done simply becomes 
- When the force is perpendicular to the motion of the object,
and
, which means that no work done - Technically, work is also done when the force is not parallel to the motion of the object: in this case, the factor
means that only the component of the force parallel to the direction of motion contributes to do work on the object.
Therefore, the correct answer is
Work is done when a force is in the same direction as the object moves.
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Answer:
Explanation:
Consider downward displacement first .
downward displacement h = 38 m .
downward acceleration = g
downward initial velocity u = 0
h = ut + 1/2 g t ²
38 = 0 + 9.8 t ²
t = 1.97 s
During this period , there will be horizontal displacement with initial velocity u = 10 m /s and acceleration a = 1.6 m /s²
s = ut + 1/2 a t²
= 10 x 1.97 + .5 x 1.6 x 1.97²
= 19.7 + 3.10
= 22.8 m