-A bus is moving with a velocity of 72 km/hr . On applying brakes the bus stops after covering a distance of 500 METERS .Required to find :- DECELERATION of the bus produced by the brakes ? Concept used :- Equations of motion Equation used :-UNITS Conversion :- Here we need to convert the velocity from meters to kilometres Reason :- Since the displacement is given in km/hr we need to convert the velocity into metres per second .1 km/hr = 5/18 m/s 72 km/hr = ? m/s => 72 x 5/18 => 20 m/sThis implies,Velocity of the bus = 20 m/sSimilarly,0 km/hr = 0 m/s SOLUTION :- Given that :- A bus is moving with a velocity of 72 km/hr ( 20 m/s )on applying brakes the bus stops after covering a distance of 500 meters So,From the above we can conclude that ;Initial velocity of the bus = 20 m/sFinal velocity of the bus = 0 m/sDisplacement = 500 meters We need to find the deceleration of the bus So,Using the 3rd equation of motion Here,v = Final velocity u = Initial velocity a = acceleration s = displacement Since negative acceleration is known as retardation or deceleration .So,By substituting the values in the equation We GET,Therefore ,Deceleration of the bus = - 0.4 m/s²