Answer:
17.64 km/h
Explanation:
mass of car, m = 1000 kg
Kinetic energy of car, K = 1.2 x 10^4 J
Let the speed of car is v.
Use the formula for kinetic energy.

By substituting the values

v = 4.9 m/s
Now convert metre per second into km / h
We know that
1 km = 1000 m
1 h = 3600 second
So, 
v = 17.64 km/h
Thus, the reading of speedometer is 17.64 km/h.
A decrease in velocity is referred to as deceleration. If car is moving at 30 m/s and stop in 50 m .The value of deceleration is 11.56 ms−2.
<h3>How to calculate deceleration ?</h3>
While acceleration is motion in which an object's speed varies every second, deceleration is motion that causes an object to slow down.
We are aware that acceleration refers to an object's rate of increase in speed, and deceleration refers to an object's rate of decrease in speed. For instance, when we apply the brakes while driving, we benefit from the vehicle's ability to decelerate and slow down.
The Deceleration Formula is the final velocity minus the initial velocity, with a negative sign in the result because the velocity is decreasing, if starting velocity, final velocity, and time taken are given.
velocity of car = 30 m/s
car need to stop in 50m
Deceleration a = v^2 – u^2 / 2s
= 0^2 - 50^2 / 2*30
= 11.56
Deceleration of the care = 11.56 ms−2
To learn more about deceleration refer :
brainly.com/question/75351
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Answer:The mass of ball B is 10 kg.
Explanation;
Mass of ball A = 
Velocity of the ball A before collision:
Velocity of ball A after collision=
Mass of ball B= 
Velocity of the ball B before collision:
Velocity of ball B after collision=



The mass of ball B is 10 kg.
Answer:
force=12000
Explanation:
F=m*a aka force equals mass times acceleration so 800*15=12000
Answer:
In the 1980s, astronomers turned to multiverse theory to explain the “luckily small” amount of dark energy in our universe. According to cosmologist's theories, this small amount of dark energy appeared to enable our universe to host life, while most universes in the multiverse couldn't.
Explanation: