Answer:
a) 0.138J
b) 3.58m/S
c) (1.52J)(I)
Explanation:
a) to find the increase in the translational kinetic energy you can use the relation
where Wp is the work done by the person and Wg is the work done by the gravitational force
By replacing Wp=Fh1 and Wg=mgh2, being h1 the distance of the motion of the hand and h2 the distance of the yo-yo, m is the mass of the yo-yo, then you obtain:
the change in the translational kinetic energy is 0.138J
b) the new speed of the yo-yo is obtained by using the previous result and the formula for the kinetic energy of an object:
where vf is the final speed, vo is the initial speed. By doing vf the subject of the formula and replacing you get:
the new speed is 3.58m/s
c) in this case what you can compute is the quotient between the initial rotational energy and the final rotational energy
hence, the change in Er is about 1.52J times the initial rotational energy
From Boyle's law, the volume of a fixed mass of a gas is inversely proportional to its pressure at constant absolute temperature.
Therefore; P1V1 =P2V2; where PV is a constant
hence; 12 × 6 = 3× p2
p2 = 72/3
= 24 atm
Therefore; the new pressure will be 24 atm
Answer:
Less friction
Explanation:
Paolo's bike is too difficult to pedal because there is too much friction in the mechanisms of the bike. To reduce friction, Paolo must oil the chain. This will make the bike run much more smoothly and allow for easier pedalling.
Answer:
I believe its A: Sports biomechanics.
Answer:
A. The upward pressure gradient force is balanced by gravity.
Explanation:
A. is correct because the pressure difference is actually generated by gravity. As in the following formula for the pressure at different points:
where 
are the pressure at 2 points, ρ is the density of the fluid, g is the gravitational constant, and h is the height difference.
B is incorrect because friction in air is too small to make an effect.
C is incorrect because the Coriolis force is horizontal, not vertical.
D is incorrect because a difference of 500 hPa = 50000 Pa, this is half of the atmospheric pressure.
E is incorrect because temperature cannot generate force.
