Answer:
Explanation:
Given that,
Kinetic energy of an automobile is 2300J
K.E = 2300J
The formula for kinetic energy is
K.E = ½mv²
So, if the speed of the automobile is increased by 6, what is the kinetic energy
Now v' = 6v.
The mass of the automobile is constant.
Therefore, the kinetic energy is
K.E' = ½mv'²
Where v' = 6v
K.E' = ½m(6v)²
K.E' = ½m × 36v²
K.E' = 36 × ½mv²
Where, from above ½mv² = 2300J
Then,
K.E' = 36 × 2300 = 82,800J
The kinetic energy of the automobile when it increase it's speed is 82,800J
Explanation:
Given that,
Diameter of the wheel, d = 70 cm = 0.7 m
Initial angular speed, 
Final angular speed, 
Time, t = 4 s
(a) Angular acceleration,

(b) Tangential acceleration is :
Angular speed of the wheel after 2 seconds is :

Radial acceleration will be :

Hence, this is the required solution.
Potential energy due to gravity = Ep = mgh [symbols have their usual meaning ]
Evidently, HALVING the mass will make Ep , HALF its previous value. So, It will be halved.