WORK AND ENERGY

A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. The work done against the gravitational force will be (g = 10 ms²)

• (a) 6 × 10³ J

• (b) 6 J

• (c) 0.6 J

• (d) zero

Tags

NGSS.HS-PS2-4

NGSS.HS-PS3-1

Which one of the following is not the unit of energy?

• (a) joule

• (b) newton metre

• (c) kilowatt

• (d) kilowatt hour

A body is falling from a height h. After it has fallen a height h/2, it will possess

• (a) only potential energy

• (b) only kinetic energy

• (c) half potential and half kinetic energy

• (d) more kinetic and less potential energy

Tags

NGSS.HS-PS3-2

The number of joules contained in 1 kWh is

• (a) 36 × 10⁵ J

• (b) 3.6 × 10⁷ J

• (c) 36 × 10⁸ J

• (d) 3.7 × 10⁷ J

Tags

NGSS.HS-PS3-1

If speed of a car becomes 2 times, its kinetic energy becomes

• (a) 4 times

• (b) 8 times

• (c) 16 times

• (d) 12 times

A dog weighing 25 kg, while chasing a cat, jumps over a fence of height 1.6 m. What is the potential energy of dog at the top of fence ?

(Take 'g'=10 m s^-2 )

• (a) 160 Joules

• (b) 320 Joules

• (c) 380 Joules

• (d) 400 Joules

Tags

NGSS.HS-PS3-1

A car with mass ‘M’ is moving on horizontal road with velocity ‘v’. Driver applies accelerator and increases it speed 3 times to ‘3v’. The final K.E. acquired by the car will be :

• (a) 1.5 Mv²

• (b) 2.5 Mv²

• (c) 3.5 Mv²

• (d) 4.5 Mv²

Tags

NGSS.HS-PS3-1

A cyclist is moving at a speed of 5 m/s on leveled road. While going down the slop, his speed increases to 7 m/s. Here the nature of work done by gravitational force in increasing the speed of cyclist is an example of ?

• (a) positive work done

• (b) negative work done

• (c) Infinite work done

• (d) Zero work done

Tags

NGSS.HS-PS2-4

NGSS.HS-PS3-2

An object is thrown vertically upward and it reaches to a maximum height 'h' from the ground. During its flight, on reaching 3/4 of height h, it will acquire?

• (a) less potential and high kinetic energy

• (b) more potential and less kinetic energy

• (c) same potential and kinetic energy

• (d) only kinetic energy

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

A body is moving with velocity 4 m/s , possesses 56 Joules of Kinetic Energy. The momentum of body will be equal to

• (a) 7 kgms^-1

• (b) 14 kgms^-1

• (c) 21 kgms^-1

• (d) 28 kgms^-1

Tags

NGSS.HS-PS2-2