A beam pivoted at one end has a force of 5.0N acting vertically upwards on it as shown. the beam is in equilibrium.
1 answer:
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Answer:
The rule for kilometers is that every three seconds between a lightning flash and the following thunder gives the distance to the flash in kilometers.
Explanation:
In order to use the rule of thumb to find the speed of sound in meters per second, we need to use some conversion ratios. We know there is 1 mile per every 5 seconds after the lightning is seen. We also know that there are 5280ft in 1 mile and we also know that there are 0.3048m in 1ft. This is enough information to solve this problem. We set our conversion ratios like this:
notice how the ratios were written in such a way that the units got cancelled when calculating them. Notice that in one ratio the miles were on the numerator of the fraction while on the other they were on the denominator, which allows us to cancel them. The same happened with the feet.
The problem asks us to express the answer to one significant figure so the speed of sound rounds to 300m/s.
For the second part of the problem we need to use conversions again. This time we will write our ratios backwards and take into account that there are 1000m to 1 km, so we get:
This means that for every 3.11s there will be a distance of 1km from the place where the lightning stroke. Since this is a rule of thumb, we round to the nearest integer for the calculations to be made easily, so the rule goes like this:
The rule for kilometers is that every three seconds between a lightning flash and the following thunder gives the distance to the flash in kilometers.
Answer:
1)H=714 Watts of energy is given out.
2)614.34 KCal energy is burnt in an hour in the room
3)In freezing conditions, 1337.09 KCal is spent in an hour.
Explanation:
The formula for thermal conductivity states that the rate of heat loss H is as follows:
H= where,
K=Coefficient of thermal conductivity
A=Area of Cross Section
H=Rate of heat loss
x=Thickness of the material
=Temperature difference between the two surfaces of the body in context
=37°C ie. Body Temperature
=20°C ie. Room Temperature
For first case, =17°C or 17°F
K for fat= 0.21
A=2
x=0.01 m
H=
H=714 Watts of energy is given out.
2) ×
Energy= 714 × 60 × 60=2570400 J
2570400 J=614.3403442 KCal
Therefore, 614.3403442 KCal energy is burnt in an hour.
3) Only the temperature difference becomes 37°C from 17°C , rest everything remains the same, therefore the energy will also vary due to the temperature factor and more energy will be spent as in freezing climate °C
E==1337.09 KCal
In freezing conditions, 1337.09 KCal is spent in an hour.
Answer:
2.08 kg
Explanation:
We can solve the problem by using Newton's second law:
where
F is the net force acting on an object
m is the mass of the object
a is its acceleration
In this problem, the ball is kicked with a force of F=13.5 N, and its acceleration is a=6.5 m/s^2, therefore we can re-arrange the equation to find the mass of the ball, m: