6. Since we are not sure if the person in the question is actively lifting the crate, we have to determine the downwards force of the crate due to gravity and compare it to the normal force.
F = ma
F = (15.3)(-9.8)
F = -150N
Since the downwards force of the crate is equivalent to the normal force, it means the person is applying no force in picking up the object. So to pick up a 150N object from scratch, you would have to exert more force than the weight of the object, so the answer is 294N.
7. Same idea as question 2.
First determine the weight of the object:
F = ma
F = (30)(-9.8)
F = -294N
The crate in question is not moving, so the magnitudes of the forces in the upwards and downwards direction has to equal to 0.
-294 + 150N + x = 0
x = 144N
So the person is exerting 144 N.
10. First find the force of block B to the right due to its acceleration:
F = ma
F = (24)(0.5)
F = 12N
So block B is moving 12N to the right relative to block A due to block A's movement to the left. However, block A is being applied a much greater force and is moving quicker to the left than block B is moving to the right of bock A. The force that is causing block B to experience the lower relative force to the right is because of the friction. To find the friction:
The sum of the forces in the leftward and rightward direction for block B must equal 12N.
75 - x = 12
x = 63N
So the force of friction of block A on block B is 63N to the left.
I believe the sun is the primary source of energy for Earth's weather system. The sun is the primary energy source for Earth's climate system which is the first set of essential principles of climate sciences. Additionally, it is the primary source that drives all weather events, including precipitation, hurricane and tornadoes. The sun drives the hydrologic cycle, and makes life on Earth possible.
Hello!
Yes, someone with an IQ score of 120 can be gifted.
An IQ score of 120 means that the individual is moderately gifted. Although this IQ doesn't qualify for gifted education programs, research shows that people with IQs of about 145-180 don't perform significantly better than people with 120s IQ in terms of success.
As an example, professor Dean Simonton from the University of California found that an optimum leader should have an IQ in the 120-125 range, so having an IQ of 120 would mean that the individual is gifted for leadership.
Have a nice day!
Answer:
37.9 kJ
Explanation:
We can calculate the thermal energy gained by the iron using the formula:
where
m = 35 g is the mass of the iron
Cs = 0.450 j/g is the iron's specific heat capacity
is the change in temperature of the iron (assuming that the room's temperature is 20 C degrees)
Substituting numbers into the formula, we find
