A bicyclist starts from rest and after travelling along a st

A bicyclist starts from rest and after travelling along a straight path a distance of 20 m reaches a speed of 30 km/h. Determine his acceleration if it is constant. Also, how long does it take to reach the speed of 30/h?

Solution

>> Initial Speed, U = 0

>> After distance , S = 20 m,

>> FInal Velocity attained, V = 30 km/h = 30*5/18 = 8.333 m/s

>> Let acceleration = \"a\" = ?

>> Now, Using Newton\'s 3rd Equation of Motion,

V² - U² = 2as

>> Putting all values,

=> 8.333² - 0 = 2*a*20

=> a = 1.736 m/s²

=> Acceleration of the bucyclist, a = 1.736 m/s²

>> Now, Using Newton\'s 1st Equation of Motion,

V = U + a*t

>> Now, Let time taken to reach speed 30 km/h = 8.333 m/s is \"t\"

>> 8.333 = 0 + 1.736*t

=> t = 4.80 sec

=> Time Required to achieve speed 30 km/h = 4.80 seconds .......ANSWER........