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soldier1979 [14.2K]
3 years ago
14

An object is dropped from a​ tower, 400 ft above the ground. The​ object's height above ground t seconds after the fall is ​s(t)

equals400 minus 16 t squared. Determine the velocity and acceleration of the object the moment it reaches the ground. The velocity of the object the moment it reaches the ground is nothing ​ft/s.
Physics
1 answer:
Paul [167]3 years ago
7 0

Answer: v= 160ft/s

a=32ft/s^2 constant

Explanation:

s(t)=400-16t^2 derivative of position is velocity v(t) and derivative of velocity is acceleration a(t) so let s(t)=0 to find the time of flight to reach the ground and take the two derivatives and use the time found and solve. Also acceleration is a constant as it’s gravity.

0=400-16t^2

400=16t^2

25=t^2

t=5s

ds/dt=v(t)=0-32t

dv/dt=a(t)=-32 constant(gravity)

v(t)=-32(5s)= -160ft/s negative sign is only showing direction

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Answer: Option (e) is the correct answer.

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There are three types of kinetic energy which are vibrational, rotational and translational kinetic energy.

A plucked string on a guitar  will produce sound and it represents vibrational kinetic energy.

The moving blades of a ceiling fan shows the rotation of blades and it represents rotational kinetic energy.

A spinning top also displays rotation therefore, it represents rotational kinetic energy.

A tuning fork struck on a rubber block will produce sound and it will vibrate. Therefore, it represents vibrational kinetic energy.

An apple falling from a tree shows that apple is linearly falls on the ground therefore, it represents translational kinetic energy.

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5 0
4 years ago
Read 2 more answers
A force in the x direction acts on a particle moving also in the x direction, producing a potential energy U(x)=Ax4 where A=0.63
poizon [28]

Answer:

The magnitude of the force is 1.29*10^-3N in the positive x direction

Explanation:

In order to calculate the magnitude and direction of the force, you take into account that the force is the space derivative of the potential enrgy, as follow:

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The magnitude of the force is 1.29*10^-3N in the positive x direction

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