Question

(a) Find the linear momentum and kinetic energy of a bullet of mass 5.70  10^-2 kg moving at a speed of 330 m/s.

linear momentum	=
kinetic energy	=

(b) Find the linear momentum and kinetic energy of a football player of mass 111 kg moving at a speed of 10.0 m/s.

linear momentum	=
kinetic energy	=

(c) Find the linear momentum and kinetic energy of a truck of mass 1.00  10⁴ kg moving at a speed of 20.5 m/s.

linear momentum	=
kinetic energy	=

Answer 1

We have the equation of linear momentum,

P= mv,

And equation of kinetic energy

KE = 1/2 ( mv​​​​​2)

where m is the mass of the body and

v is the velocity of the body.

a.given mass of the bullet,m = 5.70x10-2kg

And velocity of the bullet, v = 330 m/s.

The linear momentum of the bullet,P= mv

P = 5.70x10-2x330 = 18.81 Kg m/s

Kinetic energy KE = 1/2( mv​​​​​2)

KE = 1/2 x 5.70x10-2 x (330)2

KE = 6207.3/2 = 3103.65 Joules

b) here given mass of the player,m = 111Kg

And his velocity, v= 10 m/s

His linear momentum, P= mv= 111x 10

P= 1110 Kg m/s

His kinetic energy KE= 1/2 x mv​​​​​2

KE = 1/2 x 111x 102

​​​​​KE= 11100/2

So kinetic energy of the football player=

5550 Joules.

c. The mass of the truck = 1.0x 104kg

The velocity of the truck=20.5 m/s

Linear momentum of the truck,P= mv

P= 1.0x104 x 20.5= 205000 Kg m/s

The kinetic energy of the truck= 1/2 mv​​​​​2

KE= 1/2 x 1.0 x 104x 20.52

KE = 2101250 Joules.