show your work by writing the given formula.how much kinetic energy does a 1.2 kg ball have the moent it hits ground 3.m5 meters below its restarts from rest
Answers
Answer:
Correct answer:
20.77ms
Explanation:
We can use potential energy to solve. Remember, your height and your gravity need to have the same sign, as they are moving in the same direction (downward). Either make them both negative, or use an absolute value.
Using conservation of energy, we know that PEtop=KEbottom. This tells us that the potential energy at the top of the hill is all converted to kinetic energy at the bottom of the hill. We can substitute the equations for potential energy and kinetic energy.
mgh=12mv2
The masses cancel out.
gh=12v2
Plug in the values, and solve for the velocity.
(−9.8ms2)(−22m)=12v2
215.6m2s2=12v2
431.2m2s2=v2
431.2m2s2−−−−−−−√=v2−−√
20.77ms=v
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Example Question #1 : Calculating Kinetic Energy
A 0.5kg ball rolls down a 1m hill with an initial velocity of 2.45ms. What is its maximum velocity?
g=−9.8ms2
Possible Answers:
10.12ms
6.06ms
12.80ms
25.60ms
5.06ms
Explanation: