A track star runs a 100m race in 12s what is the velocity of the runner?
1 answer:
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This question is incomplete, the missing diagram is uploaded along this answer below.
Answer:
- the magnitude of the tension force exerted by the hamstring muscles on the leg is 990 N
- the magnitude of compression force at the knee joint is 900 N
Explanation:
Given the data in the question and diagram below;
Net torque = 0
Torque = force × lever arm
so
F × ( 15.0 in + 1.5 in ) = T
× 1.5 in
given that F = 90 N
90 × ( 15.0 in + 1.5 in ) = T × 1.5 in
90 N × 16.5 in = T × 1.5 in
T = ( 90 N × 16.5 in ) / 1.5 in
T = 990 N
Therefore, the magnitude of the tension force exerted by the hamstring muscles on the leg is 990 N
b) magnitude of compression force at the knee joint;
In equilibrium, net force = 0
along horizontal
F - T
+ F
= 0
we substitute
F - 990 + 90 = 0
F - 900 = 0
F = 900 N
Therefore, the magnitude of compression force at the knee joint is 900 N
Answer:
,
Explanation:
The force experienced by the ion due to the magnetic field is given by:
where
q is the charge
v is the speed
B is the intensity of the magnetic field
The cetripetal force is
where
m is the mass
r is the radius of the circle
Since the magnetic force acts as centripetal force, we can equate the two expressions:
Re-arranging it, we find the radius:
Now, if we want to find the time it takes for the ion to make one complete circle (=the period), we just need to divide the length of one circumference by the speed:
And susbstituting the expression we found before for r, we find