Answer:
T = 480.2N
Explanation:
In order to find the required force, you take into account that the sum of forces must be equal to zero if the object has a constant speed.
The forces on the boxes are:
(1)
T: tension of the rope
M: mass of the boxes 0= 49kg
g: gravitational acceleration = 9.8m/s^2
The pulley is frictionless, then, you can assume that the tension of the rope T, is equal to the force that the woman makes.
By using the equation (1) you obtain:
The woman needs to pull the rope at 480.2N
Answer:
B
Explanation:
B is the most likely region that contains alkaline earth family elements.
If you have a lump of solid at its melting point ... like ice at 32°F ...
you have to put a certain amount of heat into it just to change it
to water at 32°F. That amount of heat, that's used just to change
a solid lump into liquid without changing its temperature, is called
the heat of fusion for that substance.
The number is different for every substance.
For water, it takes 336 joules of heat to melt 1 gram of ice
into 1 gram of water, all at 32°F (0°C).
That's an enormous latent heat of fusion ... more than almost any
other known substance. That's why ice is such a good choice
when you need something to put in your drink to cool it down.
Ice absorbs a huge amount of heat before it melts and the drink
gets watered down.
Answer:
Option B is correct.
Power = 360 W
Explanation:
Power = Work done/time
Work done = Force × distance moved through by the force
Power = Force × (distance moved through by the force/time)
(Distance moved through by the force/time) = velocity = 3 m/s
Power = Force × velocity
Force = ma
But the acceleration in this case is this acceleration + acceleration due to gravity because the force has to be overcoming the force of gravity to now move the object upward at 2 m/s²
a = (2 + g) (assume acceleration due to gravity = 10 m/s²
a = 2 + 10 = 12 m/s²
F = ma = 10 × 12 = 120 N
Power = F × v = 120 × 3 = 360 W