A stone is projected vertically?

Question

A stone is projected vertically upward at an initial speed of 60ms^-1. Caculate

a) The maximum height reached
b) The time of flight
c) its speed when 100m high

Answer 1

The equations for this are
v(t)=60-g*t and
y(t)=60-.5*g*t^2

Step 1: find t when v(t)=0
60/g=t

this is half the flight time, using g=10
t=6 and flight time is 12 seconds

The apogee will be y(6)
y(6)=60*6-5*36
=180 m

The stone will be 100 m high on the ascent and descent.

Fine the two times using
y(t)=100=60*t-5*t^2
t= 2, 10

v(t)=60-10*t
v(2)=40 m/s
v(10) = -40 m/s


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