A seesaw remains stationary when two students of equal weight sit on the ends
c
<em>Hope</em><em> </em><em>this</em><em> </em><em>will</em><em> </em><em>help</em><em> </em><em>u</em><em>.</em><em>.</em><em>.</em><em>.</em><em>.</em><em>:</em><em>)</em>
<em>✌</em><em>✌</em><em>✌</em><em>✌</em><em>✌</em><em>✌</em>
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.
If the wavelength of a sound wave increases and the frequency of the sound wave does not change, the speed of the wave will increase.
Ans: D
Explanation
The sound wave speed is given by E=fλ, where f indicates its frequency and λ indicates its wavelength.
From the equation, it is evident that the sound speed is proportional to both frequency and wavelength.
Here, as wavelength increases, wave speed increases provided there is no change in frequency.
Periods<span> going left to right. The periodic table also has a special name </span>for<span> its vertical columns. Each column </span>is<span> called a </span>group. The elements in eachgroup<span> have the same number </span>of<span> electrons </span>in the<span> outer orbital.</span>
