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.
Potassium hydroxide (KOH) and
hydrochloric acid (HCl) react in a beaker. They form potassium chloride (KCl)
and water (H2O). This type of reaction is a double replacement reaction wherein
the two principal reactants exchange after the reaction. The Cl will combine to
the K forming KCl and the H will add to the OH forming H2O.
Answer:
a) 35.44 mm
b) 17.67 mm
Explanation:
u = Object distance = 3.6 m
v = Image distance
f = Focal length = 35 mm
= Object height = 1.8 m
a) Lens Equation
The CCD sensor is 35.34 mm from the lens
b) Magnification
The person appears 17.67 mm tall on the sensor
Answer:
7 miles northeast is the because it has both magnitude and direction .
Answer:
18.6 m/s
Explanation:
= Initial height of the balloon = 11 m
= initial speed of the ball
= initial vertical speed of the ball = 7 m/s
= initial horizontal speed of the ball = 9 m/s
initial speed of the ball is given as
= final speed of the ball as it strikes the ground
= mass of the ball
Using conservation of energy
Final kinetic energy before striking the ground = Initial potential energy + Initial kinetic energy
