Home
Class 11
PHYSICS
In a shotput event, an athlete throws th...

In a shotput event, an athlete throws the shotput of mass `10kg` with an initial speed of `1ms^(-1)` at `45^(@)` from a heigth `1.5m` above ground. Assuming air resistance to be negligible and acceleration due to gravity to be `10ms^(-2)`, the kinetic energy of the shotput when it just reaches the ground will be

A

2.5j

B

5.0j

C

52.5j

D

155.0j

Text Solution

Verified by Experts

(d) Given, h=1.5m,v=1m/s,m=10kg.g=`10ms^(-1)`
From conservation of mechanical energy.
`(PE)i+(KE)i=(PE_f+(KE)f`
`Rightarrow mgh+(1)/(2)mv^(2)=0+(KE)f`
`Rightarrow (KE)f=mgh+(1)/(2)mv^(2)`
`Rightarrow (KE)f=10xx10xx1.5+(1)/(2)xx10xx(1)^(2)`
`" " =150+5=155J`
NOTE: We should be carefull about the referemce taken for PE, it may or may not be in the ground.
Promotional Banner

Similar Questions

Explore conceptually related problems

In a shotput event an athlete throws the shotput of mass 10 kg with an initial speed of 1 ms^(-1) at 45^@ from a height 1.5 m above ground. Assuming air resistance to be negligible and acceleration due to gravity to be 10 ms^(-2) , the kinetic energy of the shotput when it just reaches the ground will be

In a shotput event an athlete throws the shotput of mass 20 kg with an initial speed of 2 m s^(-1) at 45^@ from height 3 m above ground. Assuming air resistance to be negligible and acceleration due to gravity to be 10 m s^(-2) , the kinetic energy of the shotput when it just reaches the ground will be

A stone of mass 1 kg falls to the earth from a height of 10 m. The kinetic energy of the stone when it is 4 m above the ground is

A stone of mass 1 kg falls to the earth from a height of 10 m. The kinetic energy of the stone when it is 4 m above the ground is:

If acceleration due to gravity is 10 m//s^(2) , what will be the potential energy of a body of mass 1 kg kept at a height of 5 m?

If unit of mass is taken as 1 kg of time as 1 minute and that acceleration due to gravity is taken as 9.81 ms^(-2) , what is the unit of energy ?

A man standing on the edge of the roof of a 20 m tall building projects a ball of mass 100 gm vertically up with a speed of 10 ms^(-1) . The kinetic energy of the ball when it reaches the ground will be [g = 10 ms^(-2)]

A thin ring of mass 1kg and radius 1m is rolling at a speed of 1ms^(-1) . Its kinetic energy is

A ship of mass 3xx10^7kg initially at rest, is pulled by a force of 5xx10^5N through a distance of 3m. Assuming that the resistance due to water is negligible, the speed of the ship is

A constant retarding force of 50N is allied to a body of mass 10kg moving initially with a speed of 10ms^(-1) . The body comes to rest after