Answer:
a) -3.267 m/s
b) 2.227 m/s
Explanation:
As per the conservation of momentum
m1v1 + m2v2=0
m1= mass of log
m2 = mass of lumber jack
v1 = velocity of log
v2 = velocity of lumber jack
a) Velocity of first log
m/s
b) m1v1 + m2v2 = m3v3
Velocity of log
=
The only force acting on the ball, once it left the hand of the player, is the gravitational atraction of the earth. Once the ball reaches its maximum height, it starts a free fall movement under the action of earth's gravity.
Then the magnitude of the acceleration of the ball is the gravitational acceleration, g, approximatley 9.8 m/s^2
To solve this problem we will apply the concepts related to the Doppler Effect. The Doppler effect is the change in the perceived frequency of any wave movement when the emitter, or focus of waves, and the receiver, or observer, move relative to each other.
Mathematically it can be described as
Where,
v = Speed of sound
f' = Reflected frequency
f = Emitted Frequency
= Speed of the object
Assuming that the speed of the medium is the speed of sound of 343m / s, we will then have that:
The power used by an electrical device is given by:
where V is the potential difference through the device while I is the current flowing through it.
For the cd-player in our problem,
, while the current is
Therefore, the power used is