Physics, please answer I don't understand !!?

S

Somu

New member
1) v^2 = vo^2 - 2gh
vo^2 = v^2 + 2gh
vo = sqrt(v^2 + 2gh)
= sqrt(6.8^2 + 2 * 9.8 * 32)
= 26 m/s
Ans: 26 m/s

2) S = 5.7 cm
t = 14 ms = 14 * 10^-3 s
vo = 0

S = vo t + 1/2 a t^2
5.7 = 0 + 1/2 a (14 * 10^-3)^2
5.7 = 98 * 10^-6 a
a = 5.7 / (98 * 10^-6)
a = 5.82 * 10^4 cm/s^2
1 cm = 10^-2 m = 10^-2 x 10^-3 km = 10^-5 km

Therefore
a = 5.82 x 10^4 x 10^-5 km/s^2 = 0.582 km/s^2
Ans: 0.582 km/s^2

___________________.
 
A knight sits on a castle wall during a siege.
To while away the time, he notes that boul-
ders catapulted from below land on the top of
his wall with a vertical velocity of 6.8 m/s.
The acceleration of gravity is 9.8 m/s2 .
If he is 32 m above the catapult, what is the
initial velocity of the boulders?
Answer in units of m/s.


An electron, starting from rest and moving
with a constant acceleration, travels 5.7 cm in
14 ms.
What is the magnitude of this acceleration
in km/s2?
Answer in units of km/s2.
 
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