Which of the following has the greatest amount of kinetic energy a)slice of pizza b)a person at the top of the stairs c)wind d)a
1 answer:
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Answer:
-22,150 N
Explanation:
When the youngster jumps off the platform, during the fall her initial potential energy is converted into kinetic energy, according to the law of conservation of energy. Therefore, we can write:
where the term on the left is the potential energy while the term on the right is the kinetic energy, and where
m = 50.0 kg is the mass of the youngster
is the acceleration due to gravity
h = 1.00 m is the heigth of the platform
u is the speed of the youngster as she reaches the floor
Solving for u,
Then, when the youngster hits the floor, the force exerted on her during the deceleration is given by:
where is her change in momentum, and where
m is the mass
v = 0 is the final velocity (she comes to a stop)
u = 4.43 m/s is the initial velocity
is the duration of the collision
Substituting,
And the negative sign means the direction of the force is opposite to the motion (so, upward).
Answer:
The time interval of acceleration for the bus is 2.20 seconds
Explanation:
Acceleration is the rate of change of velocity
→
where a is the acceleration, v is the final velocity, u is the initial velocity
and t is the time
The given is:
The uniform acceleration = -4.1 m/s²
The bus slows from 9 m/s to 0 m/s
We need to find the time interval of acceleration for the bus
Lets use the rule above
→ a = -4.1 m/s² , v = 0 m/s , u = 9 m/s
→
Multiply both sides by t
→ -4.1 t = -9
Divide both sides by -4.1
∴ t = 2.20 seconds
<em>The time interval of acceleration for the bus is 2.20 seconds</em>