Class 9th MCQ - Pre-NTSE Quiz

#WORK AND ENERGY

A block of mass 10 kg is dropped from a height of 10 m from the Earth's surface and it falls onto a vertical helical spring of stiffness 5000 N/m and length 50 cm as shown in the figure.The compression of the springs is(take,g=10m/s²)

#WORK AND ENERGY

Water falls from a height of 60 m at the rate of 50 kg/s to operate a turbine. The sosses due to frictional force are 10% of energy.How much power is generated by the turbine?(take,g=10m/s²)

#WORK AND ENERGY

a lorry and a car moving with the same KE are brought to rest by applying the same retarding force,then

#WORK AND ENERGY

Natural length of a spring is 60cm and its spring constant is 4000 N/m. A mass of 20 kg is hung from it. The extension produced in the spring is (take,g=9.8m/s²)

#WORK AND ENERGY

A force is applied by an engine of a train of mass 2.05×10^6 kg changes its velocity from 5m/s to 25m/s in 5min. The power of engine is

#WORK AND ENERGY

A force of 5N acts on a 1.5kg body initially at rest.the work done by the force during the first second of motion of the body is

#WORK AND ENERGY

Energy absorbed by solar panel is used to to charge battery.During the day, the battery stores 1.6 J of energy each second. At night, the battery is used to light A 1.2 W lamp for 18000 s.

#WORK AND ENERGY

Nuclear power plant operated 10^10 kW. How much mass is converted into energy per day?

#WORK AND ENERGY

Horses running on a playground and comes to a skidding stop. The force applied on the horse due to play ground is 500 N,which is directly opposed to the motion of the horse. How much work does the horse do on the playground?