Answer:
A: 15 m/s
B: 900 Meters
Explanation:
A. Average speed is equal to final velocity plus initial velocity divided by two
Va= (20+10)/2 = 15 m/s
B.
distance = speed × time
D= 15 m/s * 60s = 900 Meters
Answer:
30000 J = 30 kJ
Explanation:
Kinetic energy is the energy possessed by a moving object solely due to its motion.
You can get the K.E. of an object using the equation,
K.E. =
So you get,
K.E. =
= 30000 J = 30 kJ
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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