The distance travelled by the object during the first 4 seconds is 80 m
<h3>Definition of speed </h3>
Speed is defined as the distance travelled per unit time. Mathematically, it can be expressed as:
Speed = distance / time
With the above formula, we can obtain the distance travelled by the object in the first 4 seconds.
<h3>How to determine the distance travelled </h3>
Speed = distance / time
20 = distance / 4
Cross multiply
Distance = 20 × 4
Distance = 80 m
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Given that,
Mass of the stone, m = 400 g = 0.4 kg
Initial speed, u = 20 m/s
It is climbed to a height of 12 m.
To find,
The work done by the resistance force.
Solution,
Let v is the final speed. It can be calculated by using the conservation of energy.

Work done is equal to the change in kinetic energy. It can be given as follows :

So, the required work done is 32.99 J.
The amount of diffraction depends on the wavelength of light, with shorter wavelengths being diffracted at a greater angle than longer ones (in effect, blue and violet<span> light are diffracted at a larger angle than is red light).
I hope my answer has come to your help. God bless and have a nice day ahead!
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Answer:
A
Explanation:
The answer would be A because when feet push down on anything, the force will push down the skateboard
Friction will slow down the moving object