In order to escape the gravitational pull of our planet, any object must have an escape velocity of 7 km/s or more, anything lower than that will be slowed down by the pull of gravity, and will eventually returned to the surface of our planet. It is independent of mass, any lighter or heavier object must attain the required escaped velocity to reach space.
Explanation:
It is given that,
Initial speed of sprinter, u = 0
Final speed of sprinter, v = 10 m/s
Time taken, t = 1.28 s
a. We need to find the acceleration of sprinter. It can be calculated using first equation of motion as :



b. Final speed of the sprinter, v = 36 km/h
Time, t = 0.000355 h
Acceleration, 

Hence, this is the required solution.
Answer:
1.5F
Explanation:
Using
E= F/q
Where F= force
E= electric field
q=charge
F= Eq
So if qis tripled and E is halved we have
F= (E/2)3q
F= 1.5Eq=>> 1.5F
Answer:
Mike can travel 80 Km in 4 hours
b) 4m/s/s
This is because you divide the speed you reach, by the time it takes to get to that speed:
12m/s ÷ 3s = 4m/s/s
The units come from what you divide, meters per second ÷ seconds this can be written as m/s/s or ms-²