Answer:
Velocity of throwing = 34.335 m/s
Explanation:
Time taken by the tennis ball to reach maximum height, t = 0.5 x 7 = 3.5 seconds.
Let the initial velocity be u, we have acceleration due to gravity, a = -9.81 m/s² and final velocity = 0 m/s
Equation of motion result we have v = u + at
Substituting
0 = u - 9.81 x 3.5
u = 34.335 m/s
Velocity of throwing = 34.335 m/s
Answer:
0.3956
Explanation:
Newton's 2nd law of motion says that Force = Mass*Acceleration (f=ma) so to find the force used on the football you multiply it's mass by its acceleration.
0.43*0.92 = 0.3956.
0.4 if you round
Answer:
the knee extensors must exert 15.87 N
Explanation:
Given the data in the question;
mass m = 4.5 kg
radius of gyration k = 23 cm = 0.23 m
angle ∅ = 30°
∝ = 1 rad/s²
distance of 3 cm from the axis of rotation at the knee r = 3 cm = 0.03 m
using the expression;
ζ = I∝
ζ = mk²∝
we substitute
ζ = 4.5 × (0.23)² × 1
ζ = 0.23805 N-m
so
from; ζ = rFsin∅
F = ζ / rsin∅
we substitute
F = 0.23805 / (0.03 × sin( 30 ° )
F = 0.23805 / (0.03 × 0.5)
F F = 0.23805 / 0.015
F = 15.87 N
Therefore, the knee extensors must exert 15.87 N
Rotational motion may be described analytically for bodies undergoing pure rotation.
Answer:
Explanation:
Ignoring friction, the acceleration will double
F = ma
2F = m(2a)
