Answer:
a. 120 W
b. 28.8 N
Explanation:
To a good approximate, the only external force that does work on a cyclist moving on level ground is the force of air resistance. Suppose a cyclist is traveling at 15 km/h on level ground. Assume he is using 480 W of metabolic power.
a. Estimate the amount of power he uses for forward motion.
b. How much force must he exert to overcome the force of air resistance?
(a)
He is 25% efficient, therefore the cyclist will be expending 25% of his power to drive the bicycle forward
Power = efficiency X metabolic power
= 0.25 X 480
= 120 W
(b)
power if force times the velocity
P = Fv
convert 15 km/h to m/s
v = 15 kmph = 4.166 m/s
F = P/v
= 120/4.166
= 28.8 N
definition of terms
power is the rate at which work is done
force is that which changes a body's state of rest or uniform motion in a straight line
velocity is the change in displacement per unit time.
Answer:
The initial velocity of the ball is 28.714 m/s
Explanation:
Given;
time of flight of the ball, t = 2.93 s
acceleration due to gravity, g = 9.8 m/s²
initial velocity of the ball, u = ?
The initial velocity of the ball is given by;
v = u + (-g)t
where;
v is the final speed of the ball at the given time, = 0
g is negative because of upward motion
0 = u -gt
u = gt
u = (9.8 x 2.93)
u = 28.714 m/s
Therefore, the initial velocity of the ball is 28.714 m/s
when throwing a baseball overhand the muscles you use are
deltoids.
triceps.
latissimus dorsi.
abdominal muscles.
hips.
glutes.
so you should stretch and make sure you dont pull or hurt these muscles but you dont have to throw overhand Pitching underhand wasn't a gimmick for Gheen, it was his preferred style. He was mentioned in newspapers across the country for his unorthodox technique. An MLB umpire confirmed pitching underhand is allowed. also a good exercise to work out your arm would be A baseball push-up is meant to increase the power of your arms and core, and to increase the coordination between the two. This exercise also promotes good posture because it forces you to flex the muscles of the core in order to keep the lower back from bending.
and i'll leve you with a quick fact: Softball pitchers use an underhand motion that is not as stressful to the shoulder joint as the overhand pitch used in baseball. Softball pitchers can often pitch several games in one day, and often have an extended career of many years due to the lower stress levels on the shoulder joint.
good luck on your throwing!!
