Answer:
the initial velocity is 20 m/s and the acceleration is 2 m/s²
Explanation:
Given equation of motion, v = 20 + 2t
If V represents the final velocity of the object, then the initial velocity and acceleration of the object is calculated as follows;
From first kinematic equation;
v = u + at
where;
v is the final velocity
u is the initial velocity
a is the acceleration
t is time of motion
If we compare (v = u + at) to (v = 20 + 2t)
then, u = 20 and
a = 2
Therefore, the initial velocity is 20 m/s and the acceleration is 2 m/s²
v = initial velocity of launch of the stone = 12 m/s
θ = angle of the velocity from the horizontal = 30
Consider the motion of the stone along the vertical direction taking upward direction as positive and down direction as negative.
v₀ = initial velocity along vertical direction = v Sinθ = 12 Sin30 = 6 m/s
a = acceleration of the stone = - 9.8 m/s²
t = time of travel = 4.8 s
Y = vertical displacement of stone = vertical height of the cliff = ?
using the kinematics equation
Y = v₀ t + (0.5) a t²
inserting the values
Y = 6 (4.8) + (0.5) (- 9.8) (4.8)²
Y = - 84.1 m
hence the height of the cliff comes out to be 84.1 m
Answer:
At the end points of motion (either side) the velocity must be zero because the velocity is changing from - to + (it can't turn around around without passing thru zero,
The velocity will then increase to the midpoint of the motion.
m g h = 1/2 m v^2 where h is the vertical distance thru which the pendulum travels
