'Suppose your hand moves upward by 0.50m while you are throwing the ball. The ball leaves your hand with an upward velocity of 2
0.0 m/s. Find the magnitude of the force (assumed constant) that your hand exerts on the ball. Ignore air resistance.' Now my question is not 'What is the magnitude' but rather: why did I get (roughly) the same answer using F=ma when you were supposed to use the total mechanical energy (W+K1+U1=K2+U2). So I'm more confused about how the 2 formulas are 'related', what the force actually represents in both, when to use what and if there is an actual difference.
1 answer:
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Answer:
The unknown mass of the bullet is
Explanation:
According to Newton's laws of motion, when a net external force acts on a body of mass <u><em>m</em></u> , it results in change in momentum of the body and is given by:
Where:
P
is the linear momentum of the body
As a consequence, when there are no external forces acting on the body the total momentum remains conserved i.e.
Given:
For momentum along the y-direction to be zero, it is achieved when the equal masses are moving at angles of
θ1=180°, θ2=60°, θ3=-60°
Therefore, from conservation of momentum along x - direction:
Explanation:
It is given that,
Frequency of diagnostic ultrasound, f = 3.82 MHz = 3820 Hz
The speed of the sound in air, v = 343 m/s
(a) We need to find the wavelength in air of such a sound wave. Let it is given by λ₁
i.e.
(b) If the speed of sound in tissue is 1650 m/s .
Hence, this is the required solution.
Answer:
(A)
(B)
Explanation:
Given:
- diameter of the cylinder,
- mass of piston sealing on the top,
- initial temperature of the piston,
- initial height of piston,
- atmospheric pressure on the piston,
(A)
<u>Initial pressure of gas is the pressure balanced by the weight of piston:</u>
<em>Which is gauge pressure because it is measured with respect to the atmospheric pressure.</em>
(B)
Given:
- Final temperature,
<u>Now, volume of air initially in the cylinder:</u>
Using gas law:
........................................(1)
<em>∵In every condition of equilibrium the gas pressure will be balanced by the weight of the piston so it is an </em><em>isobaric transition</em><em>.</em>
∴
<u>Hence eq. (1) is reduced to:</u>
putting respective values: