We can use 3rd equation of motion to find the velocity of the stone just before it strikes the ground.
Height = S = 318 meters
Acceleration = a= 9.8 m/s²
Initial velocity = u = 0
Final velocity = v = ?
According to the 3rd equation of motion:
2aS = v² - u²
2(9.8)(318)=v²
v²=6232.8
⇒
v = 78.95 m/s
So, the velocity rounded of to nearest integer will be 79 meters per second.
Thus, C option is the correct answer
Force = mass x acceleration
force = 2500kg x (20m/s / 10m/s)
force = 2500kg x 2m/s^2
force = 5000kg m/s^2 = 5kN
i hope this is right (^^)
The deceleration of the rocket sled if it comes to rest in 1.1 s from a speed of 1000 km/h is
.
The acceleration in opposite direction is known as the deceleration. Basically the deceleration is negative value of the acceleration since the negative sign depicts its opposite in direction.
The given data:
time, t = 1.1 s
initial speed, u = 1000 km/h = 
final speed, v = 0 m/s
So we will be using the equation of motion, that is,
v = u + at



Hence , the deceleration of the rocket is
.
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