Answer
given,
mass of the ski = 75 Kg
speed of the skier, v = 3 m/s
time = 1.50 min = 90 s
angle of inclination, θ = 40°
distance = s x t
= 3 x 90 = 270 m
a) W = F. d cos θ
W = mg. d cos θ
W = 75 x 9.8 x 270 x cos 40°
W = 152021.52 J
work is done by the ski lift is equal to 152021.52 J
b) Power extended by the ski
![Power = \dfrac{Work\ done}{time}](https://tex.z-dn.net/?f=Power%20%3D%20%5Cdfrac%7BWork%5C%20done%7D%7Btime%7D)
![Power = \dfrac{152021.52}{90}](https://tex.z-dn.net/?f=Power%20%3D%20%5Cdfrac%7B152021.52%7D%7B90%7D)
P = 1689.13 Watt.
power is expended by the ski lift is equal to 1689.13 W.
Answer:
A Pulsar
Explanation:
Such white dwarf is a Pulsar (from pulsating star). Three main features we find in this kind of celestial body
1. Incredibly high density, in a pulsar there is not what we can define as free interspace. Everything is mass
2.- Huge rotational speed (more than hundreds of kilometer) spinning at more than hundreds of kilometer per second
3.-Intense magnetic field
Combinations of thse features make pulsar emits important amount of energies with pricese periods of time. And if on earth we look a jet of electromagnetic radiation with a precise rigurosity (at pricese period of time) is because we are looking a pulsar spinning and each time the radiation appears is a turn of the pulsar
Answer:
2.5
Explanation:
The capacitance of a parallel-plate capacitor filled with dielectric is given by
![C=kC_0](https://tex.z-dn.net/?f=C%3DkC_0)
where
k is the dielectric constant
is the capacitance of the capacitor without dielectric
In this problem,
is the capacitance of the capacitor in air
is the capacitance with the dielectric inserted
Solving the equation for k, we find
![k=\frac{C}{C_0}=\frac{3.0 nF}{1.2 nF}=2.5](https://tex.z-dn.net/?f=k%3D%5Cfrac%7BC%7D%7BC_0%7D%3D%5Cfrac%7B3.0%20nF%7D%7B1.2%20nF%7D%3D2.5)
The gravitational strength is equal to ![9.71\frac{N}{kg}](https://tex.z-dn.net/?f=9.71%5Cfrac%7BN%7D%7Bkg%7D)
Why?
Since we are given the gravity force acting (728N) and the mass (75Kg), we can calculate the gravitational strength using the following formula:
![gravityforce=mass*gravitationalStrength\\\\gravitationalStrength=\frac{gravityforce}{mass} \\\\gravitationalStrength=\frac{728N}{75kg}=9.71\frac{N}{kg}](https://tex.z-dn.net/?f=gravityforce%3Dmass%2AgravitationalStrength%5C%5C%5C%5CgravitationalStrength%3D%5Cfrac%7Bgravityforce%7D%7Bmass%7D%20%5C%5C%5C%5CgravitationalStrength%3D%5Cfrac%7B728N%7D%7B75kg%7D%3D9.71%5Cfrac%7BN%7D%7Bkg%7D)
Have a nice day!
Answer:
80m/s
Explanation:
v=u +at
but the car start from rest so intial velocity (u) =o
therefore,
v=0+4(20)
v=80m/s