A particle moves in a straight line with a constant acceleration. It changes its velocity from 10 ~ms ⁻¹ to 20 ~ms ⁻¹ while passing through a distance 135 ~m in t second. The value of t is

Step-by-step solution

Key Idea : The problem requires kinematics equations of motion. Let u and v be the first and final velocities of particle and a & s be the constant acceleration and distance covered by it. From third equation of motion array l y^2 =u^2+2 a s (20)^2 =(10)^2+2 a 135 or a = 300 2 135 = 10 9 ~ms ⁻² array Now using first equation of motion, aligned & v=u+a t & or t= v-u a = 20-10 (10 / 9) = 10 9 10 =9 ~s aligned