Answer:
Both balls will hit the ground at the same time
Explanation:
The factor which leads to ball falling is the gravity acting on the ball;
The motions along the path of both balls are independent and both balls will obey the following illustration
Using the third equation of motion
s = ut + ½at²
Where s = distance covered by both balls.
u = initial velocity of both balls. Since both balls start from rest, u = 0m/s
a = acceleration; and it's equal to acceleration due to gravity.
a = g
By substituton
s = 0 * t + ½gt²
s = 0 + ½gt²
s = ½gt²
Make t the subject of formula
gt² = 2s
t² = 2s/g
t = ±√(2s/g)
But time can't be less than 0 (in other words, negative)
So,
t = √(2s/g)
It'll take both balls √(2s/g) time to hit the floor
Power = (work done) / (time to do the work)
Work done = (force to lift the object) x (distance lifted)
In this question, the force is the (weight of the basket)+(your weight).
Work done = (weight of basket+you) x (3 meters)
Time to do the work = 6 seconds.
Power = (weights x 3 meters) / (6 seconds)
<em>Power = (1/2)·(weight of the basket+you, in Newtons) watts</em>
The toy rocket is launched vertically from ground level, at time t = 0.00 s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 72 m and acquired a velocity of 30 m/s. The rocket continues to rise in unpowered flight, reaches maximum height, and falls back to the ground with negligible air resistance.
The total energy of the rocket, which is a sum of its kinetic energy and potential energy, is constant.
At a height of 72 m with the rocket moving at 30 m/s, the total energy is m*9.8*72 + (1/2)*m*30^2 where m is the mass of the rocket.
At ground level, the total energy is 0*m*9.8 + (1/2)*m*v^2.
Equating the two gives: m*9.8*72 + (1/2)*m*30^2 = 0*m*9.8 + (1/2)*m*v^2
=> 9.8*72 + (1/2)*30^2 = (1/2)*v^2
=> v^2 = 11556/5
=> v = 48.07
<span>The velocity of the rocket when it impacts the ground is 48.07 m/s</span>
<span>How much kinetic energy does a 7.2-kg dog need to make a vertical jump of 1.2 m?
</span>Answer:
85 Joule (approx)
Explanation:
Potential energy at highest point
<span><span>P.E = mgh = 7.2 kg × 9.8 m/s2</span>×1.2 m≈85 Joule</span>
