Let h = distance (m) to the water surface.
Initial velocity, u = 0 (because the stone was dropped).
Use the formula
h = ut + (1/2)gt^2
where g = 9.8 m/s^2 (acc. due to graity)
t = time (s)
h = (1/2)*(9.8)*(3^2) = 44.1 m
Answer:
v = 7934.2 m/s
Explanation:
Here the total energy of the Asteroid and the Earth system will remains conserved
So we will have

now we know that





now from above formula

now we have

now plug in all data


Answer:
a) 17.49 seconds
b) 13.12 seconds
c) 2.99 m/s²
Explanation:
a) Acceleration = a = 1.35 m/s²
Final velocity = v = 85 km/h = 
Initial velocity = u = 0
Equation of motion

Time taken to accelerate to top speed is 17.49 seconds.
b) Acceleration = a = -1.8 m/s²
Initial velocity = u = 23.61\ m/s
Final velocity = v = 0

Time taken to stop the train from top speed is 13.12 seconds
c) Initial velocity = u = 23.61 m/s
Time taken = t = 7.9 s
Final velocity = v = 0

Emergency acceleration is 2.99 m/s² (magnitude)
Explanation:
Total mass=100+10=110
Total weight=mass×gravitational field strength
=110×10
=1100N
Work done=force×distance
=1100×10
=11000J
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Answer:

Explanation:
Force 1 
Force 2 
Acceleration at stage 2 
Generally the weight of the Craft W is given as
W= upward force(thrust)
Therefore
