You overhear two students discussing the topic of Doppler shift.
1 answer:
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Answer:
0.25m/s
Explanation:
Given parameters
m₁ = 5kg
v₁ = 1.0m/s
m₂ = 15kg
v₂ = 0m/s
Unknown:
velocity after collision = ?
Solution:
Momentum before collision and after collision will be the same. For inelastic collision;
m₁v₁ + m₂v₂ = v(m₁ + m₂)
Insert parameters and solve for v;
5 x 1 + 15 x 0 = v (5 + 15 )
5 = 20v
v = = 0.25m/s
Answer:
Both the frequency f and velocity v will increase.
When the radius reduces, the circumference of the circular path becomes smaller which means that more number of revolutions can be made per unit time as long as the force is kept constant; this is an increase in frequency.
Explanation:
The centripetal force acting on a mass in circular motion is given by equation (1);
where m is the mass of the object and r is radius of the circle. From equation one we see that the centripetal force is directly proportional to the square of the velocity and inversely proportional to the radius of the circular path.
However, according to the problem, the force is constant while the radius and the velocity changes. Therefore we can write the following equation;
Also recall that m is constant so it cancels out from both sides of equation (2). Therefore from equation we can write the following;
By observing equation (2) carefully, the ratio will with the square root increase
since
is lesser than
.
Hence by implication, the value of will be greater than
.
As the radius changes from to
, the velocity also changes from
to
.
