The boy pushed the sled for 15 seconds. The Work-Energy theorem can be applied in circumstances when a rigid body must move while being subjected to several forces.
The Work - Energy theorem states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle.
The Work-Energy theorem can be applied in circumstances when a rigid body must move while being subjected to several forces. A rigid body can only have kinetic energy because of its rigid structure, which prevents it from storing potential energy in its lattice.
The sled is initially at rest → initial velocity (u) = 0.
Final velocity (v) = 3.2 m/s
Mass of boy and sled (M) = 40 kg
Power developed (P) = 18 W = 18 Joules/sec
According to work - energy theorem -
Work done (W) = Δ E(K) = E(f) - E(i)
Therefore -
W=[tex](1/2*40*3.2*3.2-1/2*40*0)[/tex]=204 joule
Now, Power is defined as the rate of doing work -
P =[tex]pw/dt[/tex]= [tex]w/t[/tex]
18 = 204/t
t = 15 seconds
Hence, the boy pushed the sled for 15 seconds.
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The boy pushed the sled for 15 seconds.
The sled is initially at rest → initial velocity (u) = 0.
Final velocity (v) = 3.2 m/s
Mass of boy and sled (M) = 40 kg
Power developed (P) = 18 W = 18 Joules/sec
According to work - energy theorem -
Work done (W) = Δ E(K) = E(f) - E(i)
Therefore -
[tex]$\mathrm{W}=(1 / 2 * 40 * 3.2 * 3.2-1 / 2 * 40 * 0)=204 \text { joule }$[/tex]
Now, Power is defined as the rate of doing work -
[tex]&\mathrm{P}=p w / d t=w / t \\[/tex]
[tex]&18=204 / \mathrm{t} \\[/tex]
[tex]&\mathbf{t}=15 \text { seconds }[/tex]
Hence, the boy pushed the sled for 15 seconds.
To learn more about energy theorem refer to:
brainly.com/question/22236101
#SPJ1
