Answer:C
Explanation:
Power=280watts=280/1000 kilowatts
Power=0.28 kilowatts
Device use 0.28 kilowatts in 1 day
1day=24hours
Device use 0.28 kilowatts in 24hours
30days=30 x 24=720 hours
For 720 hours=(0.28x720) ➗ 24
For 720 hours=201.6 ➗ 24
For 720 hours=8.4
Answer:
- Its entropy increases.
Explanation:
Entropy is defined as a 'measure of the amount of energy in a physical system that cannot be used to do work.' It is also employed to denote randomness, disorder, or uncertainty of the arrangement/system. In the given system, the melting of ice denotes the 'increase in entropy' as the amount of energy unavailable to do work increases('absorbs 3.33 x 10³J of energy'). Thus, <u>this signifies that the entropy increases with a rise in temperature as it allows the substance to have greater kinetic energy</u>.
Answer : The static friction depends on two factors
1. Roughness of the surface
2. Force
Explanation : Friction occur when surface is not smooth.
The formula of friction is
Static friction depends on the roughness of the surface and force which is trying to push to object along the surface.
Static friction is caused by the attraction between two surfaces that are in contact. when the surface will rough and the object will heavier then the force will be larger.
Answer:
t = 4.17 [s]
Explanation:
We know that work is defined as the product of force by distance.
W = F*d
where:
F = force [N] (units of Newtons)
d = distance = 6.34 x 10⁴ [mm] = 63.4 [m]
In order to find the force, we must determine the weight of the box, the weight can be determined by means of the product of mass by gravitational acceleration.
w = m*g
where:
m = mass = 1.47 x 10⁴ [g] = 14.7 [kg]
g = gravity acceleration = 9.81 [m/s²]
w = 14.7*9.81
w = 144.2 [N]
Therefore the work can be calculated.
W = w*d
W = 144.2*63.4
W = 9142.72 [J] (units of Joules)
Power is now defined in physics as the relationship of work at a given time
P = W/t
where:
P = power = 2190 [W]
t = time [s]
Now clearing t, we have.
t = W/P
t = 9142.72/2190
t = 4.17 [s]
Answer:
Here's what I got:
Let's assume that N and E are + directions while S and W are - directions.
Wind is blowing from SW; thus, it is blowing towards NE (or at 45 deg N of E).
Dividing the wind's speed into components:y-component: +70.71 km/h; x-component: +70.71 km/h
Dividing the airplane's speed into components:y-component: -600 km/h; x-component: 0 km/h
Adding the components to get the resulting components:y-component: -529.29 km/h; x-component: +70.71
Using the Pythagorean Theorem to find the resulting speed:v^2 = y^2 + x^2 so v = 533.99 km/h
To find the angle of direction, use arctan (y/x):arctan (529.29/70.71) = 82.39 deg
ANSWER: velocity = 533.99 km/h at 82.39 deg S of E
Explanation:
