Answer:
0.001 s
Explanation:
The force applied on an object is equal to the rate of change of momentum of the object:
where
F is the force applied
is the change in momentum
is the time interval
The change in momentum can be written as
where
m is the mass
v is the final velocity
u is the initial velocity
So the original equation can be written as
In this problem:
m = 5 kg is the mass of the fist
u = 9 m/s is the initial velocity
v = 0 is the final velocity
F = -45,000 N is the force applied (negative because its direction is opposite to the motion)
Therefore, we can re-arrange the equation to solve for the time:
Answer:
Explanation:
Speed of skier without parachute
= √ 2gh
= √ 2 x 9.8 x 35
= 26.2 m / s
Speed of skier with parachute
net force downwards
mg - 200
= 60 x 9.8 -200
= 388 N
acceleration = 388 / 60
a = 6.47 m / s
v = √ 2ah
= √ 2 x 6.47 x 35
= 21.28 m / s
Answer:
<u>1.8kJ</u>
Explanation:
Formula :
<u>Energy used = Power x time</u>
<u />
===============================================================
Given :
⇒ Power = 30 W
⇒ Time = 1 minute = 60 seconds
=============================================================
Solving :
⇒ Energy used = 30 W × 60 s
⇒ Energy used = 1,800 J
⇒ Energy used = <u>1.8kJ</u>
To solve the exercise it is necessary to take into account the definition of speed as a function of distance and time, and the speed of air in the sound, as well
Where,
V= Velocity
d= distance
t = time
Re-arrange the equation to find the distance we have,
d=vt
Replacing with our values
It is understood that the sound comes and goes across the entire lake therefore, the length of the lake is half the distance found, that is
Therefore the length of the lake is 634,55m
