Answer: The efficiency Shelly does is 87.5%.
(70J/80J) x 100% = 87.5%
Answer 2: Gravitational potential energy would be considered an object 10 meters above the ground.
The solid can melt down to a liquid like state, and if you keep applying heat, it would eventually become a gas state.
Answer:
P = 4000 [W]
Explanation:
In order to solve this problem, we must first determine the work, which is defined as the product of force by distance.
W = F*d
where:
W = work [J] (units in Joules)
F = force = 1000[N]
d = distance = 2 [m]
W = 1000*2
W = 2000 [J]
And power is defined as the relationship between work and the time in which the work is done.
P = W/t
P = power [W] (units of watts)
t = time = 0.5 [s]
P = 2000/0.5
P = 4000 [W]
Answer:
3.8 in
Explanation:
A wheel and axle machine is a machine in which the wheel rotates around the rod (axle). They rotate together thereby transferring force among each other.
The formula for a wheel and axle is:
Fr * Rr = Fe * Re
Where Fr is the resistance force, Rr is the radius of the resistance force, Fe is the effort force and Re is the radius of the resistance force.
Given that: Fr = 235 lb, Fe = 45 lb, Re = 20 in / 2 = 10 in. Hence:
235 * Rr = 45 * 10
Rr = 45 * 10 / 235
Rr= 1.9 in
Diameter of axle = 2 * 1.9 = 3.8 in
Answer:
1) 3.92 J
2) 1596.08 J
3) 16.3 s ??
Explanation:
Initial Potential energy PE = mgh = 0.5(9.8)(0) = 0 J
Initial Kinetic energy KE = ½mv² = ½(0.5)80² = 1600 J
PE = 0.5(9.8)(0.80) = 3.92 J
KE = 1600 - 3.92 = 1596.08 J
Question 3 is not clear
to the point 80 cm above the ground the flight time is only 0.01 s
The time when the mass strikes ground again will be twice the time gravity takes to reduce the initial velocity to zero
t = 2(80.0 / 9.8) = 16.3 s
would not 80 m above the ground be a much more interesting point to consider?
PE = 0.5(9.8)(80) = 392 J
KE = 1600 - 392 = 1208 J
v₈₀ = √(2(1280) /0.5) = 69.5 m/s
t₈₀ = h/v(avg) = 80 / (½(80 + 69.5)) = 1.07 s
