An arrow in a bow has 70 j of potential energy. assuming no loss of energy due to heat, how much kinetic energy will it have after it has been shot?

a) 140 j
b) 70 j
c) 35 j
d) 0 j
e) 50 j

option B

Explanation:

given,

Potential energy of the arrow = 70 J

There is no loss of energy .

Kinetic energy = ?

According law of conservation of energy total energy of the system remain conserved.              

The energy can change it's form or can transfer form from one system to another.            

Here the potential energy of the arrow will completely convert into Kinetic energy.                            

Hence, Kinetic energy = 70 J

The correct answer is option B

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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