Since acceleration is constant, we can use the formula
v² - u² = 2a ∆x
where v = final velocity, u = initial velocity, a = acceleration, and ∆x = displacement. Then
0² - (20.0 m/s)² = 2 (-4.20 m/s²) ∆x
⇒ ∆x = (20.0 m/s)² / (8.40 m/s²) ≈ 47.6 m
No.
The acceleration of gravity on or near Earth's surface is 9.8 m/s² ,
not 20 m/s² .
If it were 20 m/s², then you would weigh almost exactly double
what you really weigh now.
1. Changing from solid to a liquid is called melting / fusion and happen
at the melting/ fusion point.
Reason: melting point is a temperature at which a solid melt and converts into liquid by providing heat.
2. Changing from liquid to gas is called evaporation/boiling and happens at the evaporation/boiling point.
Reason. Evaporation is a process in which molecules from surface of liquid convert into gas.
3. Changing from a gas to a liquid is called condensation and happens at the condensation point.
Reason : In condensation process gas particles converts into liquid droplets.
4. Changing from liquid to a solid is called freezing and happens at the freezing point.
Reason : Freezing is a process that convert liquid into soilid state by decreasing temperature of that specific liquid,
By applying force on the object. Force changes the direction of motion of the object. For example : a soccer player control the motion of a soccer ball by applying a force. It will change the ball's direction not its speed.