A body of mass 3 kg accelerates from 10 m/s to 20 m/s in 5 seconds due to the application of a force on it. Calculate the magnitude of this force (in N).
A person lent certain sum of money at 5% per annum simple interest and in 15 years the interest amounted to Rs 250 less than the sum lent. What was thesum lent (in Rs)?