Selina solutions

Selina solutions

Grade 8

Energy | Numericals

Question 10

Q10) A car is moving with a speed of 15 km\ h^{-1} and another identical car is moving with a speed of 30 km\ h^{-1}. Compare their kinetic energy.

Solution:

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

Let m be the mass of each car

Kinetic energy of car A = \frac{1}{2}m\times15^2=\frac{225}{5} =112.5 m J

Kinetic energy of car B = \frac{1}{2}m\ \times30^2=\frac{900}{2} = 450 m J

K.E. of car B is 4 times of K.E. of car A.

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subject-cta

Question 10

Q10) A car is moving with a speed of 15 km\ h^{-1} and another identical car is moving with a speed of 30 km\ h^{-1}. Compare their kinetic energy.

Solution:

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

Let m be the mass of each car

Kinetic energy of car A = \frac{1}{2}m\times15^2=\frac{225}{5} =112.5 m J

Kinetic energy of car B = \frac{1}{2}m\ \times30^2=\frac{900}{2} = 450 m J

K.E. of car B is 4 times of K.E. of car A.

Still have questions? Our expert teachers can help you out

Book a free class now

Want to top your physics exam ?

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Book a free class now
subject-cta
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