Projectile Motion MC (1 Viewer)

spatula232 · Aug 13, 2015

From 2002 JR Trial:
During a visit to the moon an astronaut throws a rock vertically and it reaches 20m. Acceleration due to gravity on moon is 1.6m.s^-2.
What is the speed it is thrown at?
a) 25.3m/s
b) 62.6m/s
c) 640m/s
d) 3920m/s

For some reason I kept getting 8m/s...

Fizzy_Cyst · Aug 13, 2015

spatula232 said:
From 2002 JR Trial:
During a visit to the moon an astronaut throws a rock vertically and it reaches 20m. Acceleration due to gravity on moon is 1.6m.s^-2.
What is the speed it is thrown at?
a) 25.3m/s
b) 62.6m/s
c) 640m/s
d) 3920m/s

For some reason I kept getting 8m/s...

Must be a typo. Answer is 8 for those values, however, if it was 200 rather than 20, answer would be A

spatula232 · Aug 13, 2015

awesome thanks

Silly Sausage · Aug 13, 2015

$20m=\frac{{V^2_0}sin^2\theta}{2g}$
$20m=\frac{{V^2_0}}{2(1.6ms^{-2})}$
$V_0=\sqrt{20m*2(1.6ms^{-2})}=8ms^{-1}$

Either the answers are off or there was a typo.

Projectile Motion MC (1 Viewer)

spatula232

Active Member

Fizzy_Cyst

Owner @ Sigma Science + Phys Goat

spatula232

Active Member

Silly Sausage

Well-Known Member

Users Who Are Viewing This Thread (Users: 0, Guests: 1)