Respuesta :
Explanation:
Given that,
Mass of block = 15.2 kg
(a). The block is resting on a level surface.
We need to calculate the force
Using formula of force
[tex]N = mg[/tex]
Put the value into the formula
[tex]N=15.2\times9.8[/tex]
[tex]N=148.96\ N[/tex]
(b). The block is resting on a surface tilted up at a 25.8° angle with respect to the horizontal.
We need to calculate the horizontal force
Using horizontal component
[tex]N=mg\cos\theta[/tex]
put the value into the formula
[tex]N = 15.2\times9.8\tinmes\cos(25.8)[/tex]
[tex]N=134.11\ N[/tex]
(c). The block is resting on the floor of an elevator that is accelerating downward at 2.53 m/s²
We need to calculate the force
Using balance equation
[tex]N-mg=F[/tex]
[tex]N=m(g+a)[/tex]
Put the value into the formula
[tex]N=15.2\times(9.8+2.53)[/tex]
[tex]N=187.4\ n[/tex]
(d). The block is on a level surface and a force of 155 N is exerted on it at an angle of 25.8° above the horizontal.
According to FBD,
We need to calculate the force
[tex]N+F\sin\theta=mg[/tex]
[tex]N=mg-F\sin\theta[/tex]
Put the value into the formula
[tex]N=15.2\times9.8-155\sin(25.8)[/tex]
[tex]N=81.49\ N[/tex]
Hence, This is the required solution.

The magnitude of the normal force on the 15.2kg for each of the given scenarios are;
A) N = 148.96 N
A) N = 148.96 NB) N = 134.064 N
A) N = 148.96 NB) N = 134.064 NC) N = 187.416 N
A) N = 148.96 NB) N = 134.064 NC) N = 187.416 ND) N = 81.5 N
A) We are told that the mass is 15.2 kg.
Thus; m = 15.2 kg
If the block is resting on a level surface, then the normal force acts opposite to it's weight and as such;
N - mg = 0
N = mg
N = 15.2 × 9.8
N = 148.96 N
B) We are told the block is resting on a surface tilted up at a 25.8° angle with respect to the horizontal.
Thus, resolving the force in the horizontal direction will give us the normal force as;
N = mg cos 25.8°
N = 148.96 × 0.9
N = 134.064 N
C) We are told that the block is resting on the floor of an elevator that is accelerating downward at 2.53 m/s².
Since acceleration is downwards then it means both the downward force and weight will be opposite the normal force. Thus,summation of forces gives;
N - mg - ma = 0
N = m(g + a)
N = 15.2(9.8 + 2.53)
N = 15.2 × 12.33
N = 187.416 N
D) The block is on a level surface and a force of 155 N is exerted on it at an angle of 25.8° above the horizontal.
Since the force of 155 N is acting at angle above the horizontal, then it means it's vertical component acts in the same direction as the normal force. Thus;
N + F sin 25.8 - mg = 0
Thus;
N = mg - 155 sin 25.8
N = 148.96 - 67.46
N = 81.5 N
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