Answer:
This happens in two ways. If an object is at rest and an unbalanced force pushes or pulls the object, it will move. Unbalanced forces can also change the speed or direction of an object that is already in motion.
Explanation:
Air caught in the ball of foil makes the ball less dense than water
Answer:
Work done gets doubled.
Explanation:
The work done by a force is given by :
W = Fd
Where
F is force and d is distance move
If the force is doubled and the distance moved remain the same, it would mean that the work done becomes double of the initial work done.
Answer: 15m/s
Explanation: <u>Average</u> <u>Velocity</u> is vector describing the total displacement of an object and the time taken to change its position. It is represented as:

At t₁ = 1.0s, displacement x₁ is:

x(1) = 28
At t₂ = 4.0s:

x(4) = 73
Then, average speed is

v = 15
The average velocity of a car between t₁ = 1s and t₂ = 4s is 15m/s