Respuesta :
Answer:
v=1.58 m/s
Explanation:
N=F*x*Cos(35)
N=599*2.30m*Cos 35
N=1128.54 J
Kinetic E = ½mv²
Initial kinetic energy
E= (86*(1.7)² )/ 2 = 124.27 J
gravitation potential is 0 at the bottom of the ramp
Potential E = mgh
final potential energy
E= 86 * 9.8 * 2.30m* Sin 35
E= 1111.84 J
final: total energy = 1111.84J + 124.27J = 1236.11 J
final kinetic energy = total energy - potential energy
Ek=1236.11 - 1128.54
Ek=107.57 J
E = ½mv²
107.57 = 86 * v² /2
v² = 2.50
v = 1.58 m/s
Answer:
[tex]v=2.48m/s[/tex]
Explanation:
From work-energy theorem we got that:
[tex]W=K_{2}-K_{1}=\frac{1}{2}m(v_{2}^2-v_{1}^2)[/tex] (1)
If we see the free body diagram attached we can calculate the work done by the group of students by knowing its definition given by:
[tex]W=F*s[/tex]
Where F is Force and s is distance
[tex]W=(Fcos(32)-wsin(32))(s)[/tex]
These are the forces at the x-axis that are causing the work done by the students
[tex]W=((599N)cos(32)-(86kg)(9.8m/s)sin(32))(2.3m)[/tex]
[tex]W=141.13J[/tex]
Now, we can calculate the velocity at the top of the ramp using (1)
[tex]W=\frac{1}{2}m(v_{2}^2-v_{1}^2)[/tex]
[tex]v_{2}=\sqrt{\frac{2W}{m}+v_{1}^2}=\sqrt{\frac{2(141.13J)}{86kg}+(1.70m/s)^2}=2.48m/s[/tex]