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3 years ago

An object moving with a speed of 21 m/s and has a kinetic energy of 140 J, what is the mass of the object.

Physics

2 answers:

alexira [117]3 years ago

7 0

Answer:2940

Explanation:

Masteriza [31]3 years ago

7 0

Answer:

0.635 kg

Explanation:

Recall that Kinetic energy is defined as:

K.E. = (1/2) mv²,

where

K.E = Kinetic energy = given as 140J

m = mass (we are asked to find this)

v = velocity = given as 21 m/s

Substituting the above values into the equation:

K.E. = (1/2) mv²

140 = (1/2) m (21)² (rearranging)

m = (140)(2) / (21)²

m = 0.635 kg

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Answer:

B meet A 0.01 km east of flagpole

Explanation:

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How far runners from the flagpole, when paths cross

solution

we know A and B are 5.7 + 4.5 = 10.2 km apart

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time B = x / 7 ...................1

and

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so time A = distance / velocity

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4 0

3 years ago

A bat strikes a 0.145-kg baseball. Just before impact, the ball is traveling horizontally to the right at 60.0 m/s , and it leav

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Answer:

F = -307.4 N

Explanation:

It is given that,

Mass of the baseball, m = 0.145 kg

Initial speed of the baseball, u = 60 m/s

Final speed of the baseball, $v=65\ cos(30)=56.29\ m/s$

Time of contact, $t=1.75\ ms=1.75\times 10^{-3}\ s$

(a) It is assumed to find the horizontal component of average force. It is given by :

$F=m\dfrac{v-u}{t}$

$F=0.145\dfrac{56.29-60}{1.75\times 10^{-3}}$

F = -307.4 N

So, the horizontal component of average force is 307.4 N. Hence, this is the required solution.

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