Question

Natasha weighs 530N. what is her kinetic energy as she swimsat

a constant speed, covering the distance of 72 m . in 1.0 min?

Answer 1

Answer: The kinetic energy of Natasha as she swim is 38.88 J

Step-by-step explanation:

Force is defined as the mass multiplied by the acceleration of the object.

Mathematically,

`F=m* a`

where,

F = weight of Natasha = 530 N

m = mass of Natasha = ?

a = acceleration due to gravity =
`9.8m/s^2`

Putting values in above equation, we get:

`530kg.m/s^2=m* 9.8m/s^2\\\\m=(530)/(9.8)=54kg`

Speed is defined as the rate at which an object moves with respect to time. To calculate the speed, we use the equation:

`s=(d)/(t)`

where,

d = distance traveled = 72 m

t = time taken by Natasha = 1.0 min = 60 sec (Conversion factor: 1 min = 60 s)

Putting values in above equation, we get:

`s=(72)/(60)=1.2m/s`

Kinetic energy is defined as the energy which is possessed due to its motion. It is also defined as the half of the product of mass of the object and square of the velocity of the object.

Mathematically,

`E_K=(1)/(2)mv^2`

where,

`E_K` = kinetic energy of Natasha

m = mass of the Natasha = 54 kg

v = velocity of Natasha = 1.2 m/s

Putting values in above equation, we get:

`E_K=(1)/(2)* 54* (1.2)^2\\\\E_K=38.88J`

Hence, the kinetic energy of Natasha as she swim is 38.88 J