Question

(c) A ball of mass 0.5 kg slows down from a speed of 5 m/s to that of 3 m/s. Calculate the change in kinetic
energy of the ball. State your answer giving proper units.
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Answer 1

Answer:

hope it helps you ..... .

Answer 2

Answer:

-4 Joules

Explanation:

$\underline{\bigstar\:\textsf{Given:}}$

• Mass (m) = 0.5 kg
• Final velocity (v) = 3 m/s
• Initial velocity (u) = 5 m/s

$\underline{\bigstar\:\textsf{To\:find:}}$

• Kinetic energy of ball (K.E) = ?

$\underline{\bigstar\:\textsf{Solution:}}$

Kinetic energy :- Energy possessed by the virtue of motion of a body. It is given by the expression K.E = ½mv²

$\:\:\:\:\:$ So, Change in kinetic energy = ½mv² - ½mu².

$\longmapsto\:\sf{\Delta\:K.E\:=\:\dfrac{1}{2}\:\times\:0.5\:\times\:(3)^2\:-\:\dfrac{1}{2}\:\times\:0.5\:\times\:(5)^2}$

$\:$

$\longmapsto\:\sf{\Delta\:K.E\:=\:\dfrac{5}{2\:\times\:10}\:\times\:9\:-\:\dfrac{5}{2\:\times\:\cancel{10}}\:\times\:\cancel{25}}$

$\:$

$\longmapsto\:\sf{\Delta\:K.E\:=\:\cancel{\dfrac{45}{20}}\:-\:\dfrac{5\:\times\:5}{2\:\times\:2}}$

$\:$

$\longmapsto\:\sf{\Delta\:K.E\:=\:\dfrac{9}{4}\:-\:\dfrac{25}{4}}$

$\:$

$\longmapsto\:\sf{\Delta\:K.E\:=\:2.25\:-\:6.25}$

$\:$

$\large\longmapsto\underline{\boxed{\sf\purple{Change\:in\:kinetic\:energy\:=\:-4\:J}}}$