Answer:
4 m/s
Explanation:
KE=1/2mv^2
720=1/2(90)
720=45v^2
divide by 45
16= v^2
over the square root
4=v
v= 4m/s
(a) The magnitude of the wind as it is measured on the boat will be the result of the two vectors. Since they are at 90°, the resultant can be determined by the Pythagorean theorem.
R = sqrt ((20 knots)² + (17 knots)²)
R = sqrt (400 + 289)
R = 26.24 knots
The direction of the wind will have to be angle between the boat and the resultant.
cos θ = (20 knots)/(26.24 knots)
θ = 40.36°
Hence, the direction is 40.36° east of north.
(b) As stated, the wind is blowing in the direction that is to the east. This means that it only has one direction. Parallel to the motion of the boat, the magnitude of the wind velocity will have to be zero.
Answer:
I_v = 2,700 W / m^2
I_m = 610 W / m^2
I_s = 16 W / m^2
Explanation:
Given:
- The Power of EM waves emitted by Sun P_s = 4.0*10^26 W
- Radius of Venus r_v = 1.08 * 10^11 m
- Radius of Mars r_m = 2.28 * 10^11 m
- Radius of Saturn r_s = 1.43 * 10^12 m
Find:
Determine the intensity of electromagnetic waves from the sun just outside the atmospheres of (a) Venus, (b) Mars, and (c) Saturn.
Solution:
- We know that Power is related to intensity and surface area of an object follows:
I = P / 4*pi*r^2
Where, A is the surface area of a sphere models the atmosphere around the planets.
a)
- The intensity at the surface of Venus is calculated as:
I_v = P_s / 4*pi*r^2_v
I_v = 4.0*10^26 / 4*pi*(1.08*10^11)^2
I_v = 2,700 W / m^2
b)
- The intensity at the surface of Mars is calculated as:
I_m = P_s / 4*pi*r^2_m
I_m = 4.0*10^26 / 4*pi*(2.28*10^11)^2
I_m = 610 W / m^2
c)
- The intensity at the surface of Saturn is calculated as:
I_s = P_s / 4*pi*r^2_s
I_s = 4.0*10^26 / 4*pi*(1.43*10^12)^2
I_s = 16 W / m^2
Answer:
Average speed of car in the first trip is 10 km/hr
Explanation:
It is given that first the car drives 6 hours to the east
Then travels 12 km to west in 3 hours
Average speed for the entire trip = 8 km/hr
Total time = 3+6 = 9 hour
So distance traveled in 9 hour = 9×8 = 72 km
As the car travel 12 km in west so distance traveled in east = 72-12 = 60 km
Time by which car traveled in east = 6 hour
So speed 
So average speed of car in the first trip is 10 km/hr
The light from the sun is reflected by the moon, we see the part of the moon that the sun shines on.The change in the phases are created from the rotation of the moon around earth.We see a full moon when the sun is opposite of the moon. The side the sun shines on the moon is what we see.
