Question

DA car is moveing with a speed of Gomis due
to east. The weight of the car is 3000 Newtons
Find the momentum of the car?​

Answer 1

Answer:

PHYSICS

A car weighing 1400kg is moving at a speed of 54km/hr up hill when the motor stops. If it is just able to reach the destination which is at a height of 10m above the point calculate the work done against friction (negative of the work done by the friction).

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ANSWER

Car Mass m=1400 kg .

h=10m

Moving at Initial speed v=54 km/h=15m/sec.

Now Initial Kinetic Energy of the car ,

=

2

1

mv

2

=

2

1

×(1400×15

2

)

=157500 J.

Here final velocity and Final Kinetic energy both are Zero.

Now change in Kinetic Energy

= Final - Initial

=0−157500

=−157500 J.

So change in Kinetic energy is also equal to Work done by all force.

Thus work done by gravity,

=mgh

=1400×9.8(−10)

=1400×−98

=−137200 .

Here, change in Kinetic energy = Work done by the friction + Work done by the gravity.

−157500= Work done by friction +(−137200)

Work done by the friction =−157500+137200

=−20,300

Hence, the work done against the friction =20300 J