Respuesta :
Answer:
The work done by the man is 260 J.
(E) is correct option.
Explanation:
Given that,
Force = 80 N
Distance = 5.0 m
Angle = 30°
Acceleration = 1.5 m/s²
Let F be the man's force
We need to calculate the force
Using balance equation
[tex]F-mg\sin\theta=ma[/tex]
[tex]F-80\sin30=\dfrac{80}{9.8}\times1.5[/tex]
[tex]F=\dfrac{80}{9.8}\times1.5+80\sin30[/tex]
[tex]F=52\ N[/tex]
We need to calculate the work done by the man
Using formula of work done
[tex]W=F\dotc d[/tex]
[tex]W=52\times 5.0[/tex]
[tex]W=260\ J[/tex]
Hence, The work done by the man is 260 J.
If the speed of the crate decreases at a rate of 1.5 m/s2, then the work done by the man is E) 260 J
Explanation:
Work is the quantity of energy transferred by displacement. The following is formula of work done
[tex]\Delta KE = F*d[/tex]
Whereas the following is formula for balance equation:
[tex]F-mg\sin\theta=ma[/tex]
The equation above is come from Newton's Second Law. It applies to a wide range of physical phenomena, but it is not a fundamental principle like the Conservation Laws and also it applies only if the force is the net external force.
- Force = 80 N, therefore
- Mass = Force/g = 80 N / 10 = 8 kg
- Distance = 5.0 m
- Angle = 30°
- Acceleration = 1.5 m/s²
For the Case of fictionless slope, the speed at the bottom of a frictionless incline does not depend upon the angle of the incline
Then the work done by the man is...
[tex]w = mgd* sin\theta + \Delta KE\\w = 80 N *5.0 m *sin 30 + (F*d)\\w = 80 N *5.0 m *\frac{1}{2} + (F*d)\\w = 40 N *5.0 m+ (F*d)\\w = 40 N *5.0 m+ (m*a*d)\\w = 200 Nm+ (8*1.5*5)\\w = 200 Nm+ 60\\w = 260 J\\[/tex]
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