<span>The energy removed from a 450 g block of ice can only be done with a few options: a colder freezing facility, liquid nitrogen, or stopping the energy at all and adding dry ice for a brief period. The 450 g block should loose heat energy faster in a thermostat set at -20 degrees just to maintain the ice formation.</span>
Answer:
b) 188 N
c) 275 N
Explanation:
Draw a free body diagram of the box. There are four forces:
Applied force F at an angle θ
Weight mg pulling down
Normal force Fn pushing up
Friction force Ff pushing left
(b)
Sum of the forces in the x direction:
∑F = ma
F cos θ − Ff = 0
Ff = F cos θ
Ff = 200 cos 20°
Ff = 188 N
(c)
Sum of the forces in the y direction:
∑F = ma
F sin θ + Fn − mg = 0
Fn = mg − F sin θ
Fn = (35)(9.8) − 200 sin 20°
Fn = 275 N
Answer:
A point on the outside rim will travel 157.2 meters during 30 seconds of rotation.
Explanation:
We can find the distance with the following equation since the acceleration is cero (the disk rotates at a constant rate):
Where:
v: is the tangential speed of the disk
t: is the time = 30 s
The tangential speed can be found as follows:
Where:
ω: is the angular speed = 100 rpm
r: is the radius = 50 cm = 0.50 m
Now, the distance traveled by the disk is:
Therefore, a point on the outside rim will travel 157.2 meters during 30 seconds of rotation.
I hope it helps you!
<span>A photon is characterized by either a wavelength, denoted by λ or equivalently an energy, denoted by E. There is an inverse relationship between the energy of a photon (E) and the wavelength of the light (λ) given by the equation:
E=hc/λ
E=hc/λ
where h is Planck's constant and c is the speed of light. The value of these and other commonly used constants is given in the constants page.
h = 6.626 × 10 -34 joule·s
c = 2.998 Ă— 108 m/s
By multiplying to get a single expression, hc = 1.99 Ă— 10-25 joules-m
E=hc/λ
(6.626*10^-34 J*s) x (2.998Ă—10^8m/s)/ 1.5*10^-8 m
= 1.32*10^-17 J</span>
<span>The moving car transfers kinetic energy to the parked car. </span>
