Answer:
The length of her shadow is changing at the rate -2 m/s
Explanation:
Let the height oh the street light, h = 22 ft
Let the height of the woman, w = 5.5 ft
Horizontal distance to the street light = l
length of shadow = x
h/w = (l + x)/x
22/5.5 = (l + x)/x
4x = l + x
3x = l
x = 1/3 l
taking the derivative with respect to t of both sides
dx/dt = 1/3 dl/dt
dl/dt = -6 ft/sec ( since the woman is walking towards the street light, the value of l is decreasing with time)
dx/dt = 1/3 * (-6)
dx/dt = -2 m/s
Answer:
Explanation:
heat lost by water will be used to increase the temperature of ice
heat gained by ice
= mass x specific heat x rise in temperature
1 x 2090 x t
heat lost by water in cooling to 0° C
= mcΔt where m is mass of water , s is specific heat of water and Δt is fall in temperature .
= 1 x 2 x 4186
8372
heat lost = heat gained
1 x 2090 x t = 8372
t = 4°C
There will be a rise of 4 degree in the temperature of ice.
Answer:
See the explanation below.
Explanation:
If you connect the three bulbs 20 W each will have a total power of 60W.
Now we need to understand to assign the meaning of the word gap, that is, if the circuit is open at that point or if there is no bulb connected at that point.
If the circuit is open at Point 2, there will be no current in the circuit, so the battery will drain faster with the three bulbs 20W.
In the second event, where gap means that there are no bulbs connected at that point, it means that you have two bulbs connected in series of 80W each.
In this case the bulbs will consume 160W thus drain the battery faster than the three 20W bulbs connected in series.
That they travel in a vacuum. All other waves require a medium in which they wave.
Explanation:
The new volume of water = 25 ml
The old volume of water = 15 ml
The difference = 25 - 15 but what are the units?
Since the question asks for force, the units must start out as 10 mL
In water 1 mL has a mass of 1 gram, so the answer is 10 grams.
Grams are units of mass, not weight. You should convert this into newtons.
10 grams = 1/1000 = 0.01 kg
1 kg has a weight of 9.81 Newtons
0.01 kg has a weight 0.081 Newtons
If you have never seen a Newton before, then the answer is 10 grams