Question

A dummy is fired vertically upward from a canon with a speed of 40 m/s. How long is the dummy in the air? What is the dummies maximum height?

Answer 1

Answer:

8,1549 seconds

81,5494 meters is the maximum height

Explanation:

REmemeber that in physiscs the formula for maximum height is given by the next representation:

$H=\frac{Vo^2}{g}$

Sow we just have to insert the values into the formula:

$H=\frac{Vo^2}{2g}\\H=\frac{40^2}{2*9,8}\\h=\frac{1600}{19,62}\\h=81.5494meters$

Now the time that it takes the dumy to fall from that height is given by thenext formula, and then we just multiply that by 2 to calculate the time that the dummy was in the air:

$t=\sqrt{\frac{2d}{g} }$

Now we insert the data we have into the formula:

$t=\sqrt{\frac{2d}{g} } \\ t=\sqrt{\frac{2(81,5494)}{9,8} }\\t=\sqrt{\frac{16309}{9,81} } \\\\t=4,077s$

in free fall the amount of time it takes an object going up is the same amount of time it take to fall, so we just multiply the time falling by 2 and we get taht the dummy was in the air for 8.1549 seconds.

Answer 2

KINEMATICS

Uniform or constant motion in a straight line (rectilinear). Speed or velocity constant and/or acceleration constant. If motion is up and down and/or has an up and down component then acceleration omn earth will be g. g is about 10m/s/s.

speed = distance/time

velocity = displacement/time

s=distance ... u=initial speed ... v = final speed ... a = acceleration ... t = time

v=u+at

v^2=u^2+2as

s=ut+1/2at^2