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nasadall
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Homework Statement
d) A stone is thrown upward with a velocity of 20m/s. Calculate:
i) How long does it take for the stone to reach its highest point;
ii) the maximum height it will achieve?
Please help
AlchemistK said:The initial velocity, u = 20m/s
The final velocity will be zero at the top most point as the stone will stop at its maximum height
thus, final velocity, v = 0m/s
the acceleration,gravity(negative as it is pulling the stone down) = 10m/s^2 (use 9.8 for accurate results)
by the first equation of motion, v = u + at
=> 0 = 20 +(-10)t
=>-20=-10 t
=>t = 2
by the third equation of motion,
v^2 + u^2 = 2as
=> 0^2 + 20^2 = 2 X -10 X s
on solving,
s = 20 m
thus, maximum height is 20 m and the time taken is 2 seconds
( 10^2 means 10 squared)
PhanthomJay said:Your getting hung up on the algebra and plus/minus sign when you multiply or divide.
If - 20 = - 10t, then multiply both sides by (-1)
(-20)(-1) = (-10t)(-1)
+ 20 = +10t
t = +2 seconds
In order to calculate time in a velocity/gravity situation, you can use the equation t = √(2h/g), where t is time, h is height, and g is the acceleration due to gravity.
The greater the velocity of an object, the less time it takes for it to fall due to gravity. This is because the velocity contributes to the object's overall speed and acceleration.
The relationship between time and acceleration due to gravity is inverse. This means that as time increases, acceleration due to gravity decreases and vice versa.
Yes, air resistance can affect the time taken for an object to fall. The greater the air resistance, the longer it will take for an object to fall due to gravity.
No, in order to calculate the time taken for an object to fall, you need to know either the height or velocity (or both) of the object. This is because these variables are essential in determining the acceleration due to gravity, which is needed to calculate time.