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.
Answer:
• They depend solely on the load that generates it
• Two or more electrical charges interact, which can be positive or negative
• The energy source is based on the electrical voltage
Answer:
2 m/s and -2 m/s
Explanation:
The object travels with an angle of
60.0°
with the positive direction of the y-axis: this means that it lies either in the 1st quadrant (positive x) or in the 2nd quadrant (negative x).
If it lies in the 1st quadrant, the value of vx (component of v along x direction) is:

If it lies in the 2nd quadrant, the value of vx (component of v along x direction) is:

<u>Answer:</u>
Mass of C in 3.40 g of HCN =1.51 gram.
<u>Explanation:</u>
Mass of sample of HCN = 7.99 g
Mass of H in 7.99 g of HCN = 0.296 g
Mass of N in 7.99 g of HCN = 4.14 g
Mass of C in 7.99 g of HCN = (7.99-0.296-4.14) = 3.554 g
Now mass of HCN = 3.40 g
Mass of C in 3.40 g of HCN = 
So mass of C in 3.40 g of HCN =1.51 gram.
Answer:
29.76245 rad/s², -117.80972 rad/s²
28.2743 rad/s
3.95833
Explanation:
= Final angular velocity
= Initial angular velocity
= Angular acceleration
= Angle of rotation
t = Time taken
Equation of rotational motion

Angular acceleration during speed up is 29.76245 rad/s²

Angular acceleration during spin down is -117.80972 rad/s²
Angular speed is given by

Maximum angular speed reached by the flywheel is 28.2743 rad/s


The ratio would be 