The kinetic energy of an object of mass, m moving with a velocity of 5m\s is 25j. What will be its kinetic energy when its velocity is doubled? What will be its kinetic energy when its velocity is increased three times?
Answers
Let the mass be m
v = 5m/s
K.E = 25 J
K.E = 1/2 mv^2
25 = 1/2 m (5)^2
25 x 2 = 25m
m = 2 kg
Now if the velocity becomes 3 times then the velocity is 3 x 5 = 15m/S
Now new K.E = 1/2 x 2 x 15^2
= 225 J
Hope it helps you
ANSWER :
KINETIC ENERGY OF AN OBJECT : The energy possessed by an object due to its motion is known as kinetic energy of that object.
K.E = 1/2 mv²
Where "m" is mass of the object and "v" is velocity of the object.
VELOCITY :The rate of change of position of a body is called velocity.
- S.I UNIT : m/s
- Vector Quantity.
→ Kinetic Energy = 25J
Velocity ( v ) = 5m/s
Kinetic Energy = 1/2 mv²
25 = 1/2 m ( 5 )²
∴ m = 2kg
i) If velocity is doubled = 10 m/s, m = 2kg
Kinetic Energy = 1/2 mv²
= 1/2 ( 2 ) × ( 10 )²
= 100J Kinetic Energy will become four times.
ii) If velocity is 3 times v = 15 m/s , m = 2kg
Kinetic Energy = 1/2 mv²
= 1/2 × 2 × ( 15 )²
= 255 J Kinetic Energy will become nine times.