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
The heat released by the water when it cools down by a temperature difference
is
where
m=432 g is the mass of the water
is the specific heat capacity of water
is the decrease of temperature of the water
Plugging the numbers into the equation, we find
and this is the amount of heat released by the water.
Answer:
a) 
b) 
c) Compressing is easier
Explanation:
Given:
Expression of force:
where:
when the spring is stretched
when the spring is compressed
hence,
a)
From the work energy equivalence the work done is equal to the spring potential energy:
here the spring is stretched so, 
Now,
The spring constant at this instant:
Now work done:
b)
When compressing the spring by 0.05 m
we have, 
<u>The spring constant at this instant:</u>
Now work done:
c)
Since the work done in case of stretching the spring is greater in magnitude than the work done in compressing the spring through the same deflection. So, the compression of the spring is easier than its stretching.
Answer:
The frequency of radiation is 
Explanation:
Given:
Wavelength 
m
Speed of light 
For finding the frequency of radiation,
Therefore, the frequency of radiation is
Answer:
F = 2.01*10^-16N -^k
Explanation:
In order to calculate the magnetic force perceived by the bee, you use the following formula:
(1)
q: charge of the bee = 1pC = 1*10^-12 C
The average speed of a bee and the magnetic field of the earth are:
v = 6.70m/s
B = 30*10^-6 T
The bee is flying to the west (-^i). You consider that the magnetic field direction is to the north (^j). Then, the direction of the magnetic force is:
-^i X ^j = -^k
You replace the values of the parameters in the equation (1), in order to calculate the magnitude of the force:
The magnetic force perceived by the bee is 2.01*10^-16N in the -^k direction, that is, toward the ground
