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viva [34]
3 years ago
12

The potential energy of a catapult was completely converted into kinetic energy by releasing a small stone with a mass of 20 gra

ms. The velocity of the stone when it reached the target was 15.0 meters/second. What was the value of the kinetic energy of the stone when it reached the target?
Physics
2 answers:
vaieri [72.5K]3 years ago
6 0

Answer: 2.25 J

Explanation: Kinetic energy is the energy possessed by an object by virtue of its motion.

K.E=\frac{1}{2}\times mv^2

m= mass of object= 20 g = 0.02 kg     (1 kg= 1000 g)

v= velocity of object= 15 m/s

K.E=\frac{1}{2}\times 0.02\times 15^2=2.25kgm^2s^{-2}=2.25J

(1J=1kgm^2s^{-2})

DerKrebs [107]3 years ago
4 0

1,000 grams = 1 kilogram
20 grams = 0.02 kilogram

Kinetic energy = (1/2) (mass) x (speed)²

                           (1/2) (0.02) x (15)² =

                                 (0.01)  x  (225)  =  2.25 joules
 
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Energy to lift something =

               (mass of the object) x (gravity) x (height of the lift).

BUT ...

This simple formula only works if you use the right units.

Mass . . . kilograms
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Height . . . meters

For this question . . .

Mass = 55 megagram = 5.5 x 10⁷ grams = 5.5 x 10⁴ kilograms

Gravity (on Earth) = 9.8 m/second²

Height = 500 cm  =  5.0 meters

So we have ...

Energy = (5.5 x 10⁴ kilogram) x (9.8 m/s²) x (5 m)

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7 0
2 years ago
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crimeas [40]

Here it is an application of Newton's III law

as we know by Newton's III law that every action has equal and opposite reaction

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Now similar way we can say

from back side of the boat the boy jumps off with force 60 N which means as per Newton's III law if boy has a force of 60 N in backward direction then he must apply a reaction force on the boat in reverse direction of same magnitude

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kumpel [21]

Answer:

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velikii [3]
Let s = rate of rotation 
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5 0
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What is kinematics..???​
swat32

Answer:

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