Respuesta :
The change in KE is more for speed change from 20 to 30 km/h
Step-by-step explanation:
Let the mass of car be m.
Speed change from 10 to 20 km/h.
Initial speed = 10 km/hr
Initial KE = 0.5 x m x 10² = 50 m
Final speed = 20 km/hr
Final KE = 0.5 x m x 20² = 200 m
Change in KE = 200m - 50m = 150m
Speed change from 20 to 30 km/h.
Initial speed = 20 km/hr
Initial KE = 0.5 x m x 20² = 150 m
Final speed = 30 km/hr
Final KE = 0.5 x m x 30² = 450 m
Change in KE = 450m - 200m = 250m
The change in KE is more for speed change from 20 to 30 km/h
The changes in the kinetic energy of the car will be more when it goes from 20 to 30 km/h.
What is Kinetic energy?
The kinetic energy of an object is the energy within the object due to its motion.
[tex]KE =\dfrac{1}{2}mv^2[/tex]
We know the formula of the kinetic energy of the car, therefore, we will calculate the change in kinetic energy in both cases when the car is moving from 10 to 20 km/h and when the class is moving 20 to 30 km/h.
Change in kinetic energy when it goes from 10 to 20 km/h
In order to calculate the change in kinetic energy of the car when it is moving from 10 to 20 km\h. we need to convert the velocity to m/s from km/h.
[tex]v_2= 20\ {\rm km/h} = \dfrac{20 \times 1000}{3600} = 5.5556\ {\rm m/s}[/tex]
[tex]v_1= 10\ {\rm km/h} = \dfrac{10\times 1000}{3600} = 2.7778\ {\rm m/s}[/tex]
[tex]\begin{aligned}\triangle KE &= \dfrac{1}{2}m(v_2^2-v_1^2)\\\\&=\dfrac{1}{2}m (5.5556^2 - 2.7778^2)\\\\& = 11.574m\end{aligned}[/tex]
change in kinetic energy when it goes from 20 to 30 km/h
In order to calculate the change in kinetic energy of the car when it is moving from 20 to 30 km\h. we need to convert the velocity to m/s from km/h.
[tex]v_2= 30\ {\rm km/h} = \dfrac{30 \times 1000}{3600} = 8.3334\ {\rm m/s}[/tex]
[tex]v_1= 20\ {\rm km/h} = \dfrac{20 \times 1000}{3600} = 5.5556\ {\rm m/s}[/tex]
[tex]\begin{aligned}\triangle KE &= \dfrac{1}{2}m(v_2^2-v_1^2)\\\\&=\dfrac{1}{2}m (8.3334^2 - 5.5556^2)\\\\& = 19.29m\end{aligned}[/tex]
Hence, the change in the kinetic energy of the car will be more when it goes from 20 to 30 km/h.
Learn more about Kinetic Energy:
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