A race car has a mass of 710 kg. It starts from rest and travels 40.0m in 3.0 s. The car is uniformly accelerated during the entire time. What net force is exerted on it?

An express train is moving with a velocity $\mathbf { V } _ { 1 }$ Its driver finds another train is moving on the same track in the same direction with velocity $v _ { 2 }$ s. To escape collision. driver applies retardation a on the train. The minimum time of escaping collision will be ;

1.5 kg ভরের একটি মডেল হেলকপ্টারের আদি গতিবেগ 5ĵ m/s. 2sec সমত্বরণে চলার পর তার গতিবেগ হয় (6î + 12ĵ) m/s. এই সময়ে প্রযুক্ত বলের মান নির্ণয় কর। 

The moment P (in $kg\, ms^{-1}$) of a particle is varying with time t (in second) as $p=2+3t^2$. The force acting on the particle at $t=3s$ will be ;

A car running with a velocity 72 kmph on a level road, is stopped after travelling a distance of 30 m after disengaging its engine $\left( g={ 10ms }^{ -2 } \right)$. The coefficient of friction between ;& ;the road and the tyres is.