Challenge

Questions uploaded after the challenge

Q1. How fast should a girl of 40 kg run so that her kinetic energy is 320J? (May 29th 2021)

A. 64 m/s

B. 8 m/s

C. 4 m/s

D. 16 m/s

Ans: 4 m/s

Q2. A horizontal force of 300 N acts for a distance of 15 m on a box of mass 90 kg. What would be the velocity of the box if it starts from rest and friction is neglected? (June 4th 2021)

Ans: 10 m/s

(First find work done. Since work done is also equal to KE, use KE equation to find v)

F x S = 1/2 x mv²

Q4. Find the mass of water used in the calorimeter for the following data given below.

A Calorimeter of mass 70 grams and specific heat capacity 0.42 J/ g ℃ contains some mass of water at 20 ℃. A metal piece of mass 30 grams at 100℃ is dropped into the calorimeter. After stirring, the final temperature is found to be 23℃. (Specific Heat capacity of metal piece: 0.3 J/g ℃ Specific Heat capacity of water: 4.2 J/g ℃

(June 19,2021)

Ans: 48 g

Q5. Pema, whose mass is 40 kg runs up a staircase of 45 steps in 5.2 seconds. Each step in the staircase is 16 cm high. Calculate the power developed by him. (g=10m/s^2 )

Ans: 553.84 watts