The answer is Balance. hopei helped? ahahahaha
bonsoir, je peux vous aider avec les maths laissez-moi comprendre merci
The minimum initial velocity that the ball must have for it to reach the top of the hill is 21 m/s. The correct option is D.
<h3>What is mechanical energy?</h3>
The mechanical energy is the sum of kinetic energy and the potential energy of an object at any instant of time.
M.E = KE +PE
A boy is trying to roll a bowling ball up a hill. The friction is ignored. The ball must have to reach the top of the hill with a velocity. The acceleration due to gravity, g = 9.8 m/s²
The conservation of energy principle states that total mechanical energy remains conserved in all situations where there is no external force acting on the system.
M.E bottom of hill = M.E on top of hill
Kinetic energy + Potential energy = Kinetic energy + Potential energy
1/2 mu² + 0 = 0 + mgh
At the top of hill, the velocity will become zero. So, final kinetic energy is zero.
Substituting the values, we have
1/2 x u² = 9.8 x 22.5
u = sqrt [2 x9.8 x 22.5 ]
u= 21 m/s
Thus, the minimum initial velocity that the ball must have for it to reach the top of the hill is 21 m/s.
Learn more about mechanical energy.
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Answer:
Athlete A
Explanation:
Power is the rate of doing work and it is calculated as follows:
Power = work done/time taken = mgh/t
(for work being done against gravity)
So for athlete A
P = (100 kg * 9.8 N/kg* 0.6m)/0.5 s = 1176 W
For athlete B
P = (150 kg * 9.8 N/kg* 0.6m)/1 s = 882 W
For athlete C
P = (200 kg * 9.8 N/kg* 0.6m)/2 s = 588 W
For athlete D
P = (250 kg * 9.8 N/kg* 0.6m)/2.5 s = 588
There are two interchangeable concepts that can be applied to this theory. The first one is the moment of Inertia and the second the perioricity. When the runners put their leg forward they reduce their moment of inertia allowing their center of mass to maintain the speed they carry and not waste energy. In this way when they swing, the leg begins to act as a kind of pendulum, and remember that the pendulum is directly proportional to the length, that is,
In this way, by bringing their legs closer they reduce the distance and make the period shorter.
