Phyics
posted by Marlerne .
A box of mass 14.0 kg sits on a horizontal steel ramp 4.8 m long with a coefficient of static friction of 0.40 between the ramp and the box. The end of the ramp is slowly lifted until the box begins to slide down the ramp. What angle does the ramp make with the ground when this happens?
Once the box begins to slide down the ramp, the coefficient of kinetic friction is 0.26. How fast will the box be moving once it reaches the bottom of the ramp?

Phyics 
Elena
1.
x: ma=mg•sin α –F(fr)
y: 0=mg•cos α +N
ma=0
0= mg•sin αμN=
= mg•sin αμ•mg•cos α
tan α = μ =0.4
α=arctan0.4 =21°
2.
ma=mg•sin α – μ₁mg•cos α
a=g•(sin α – μ₁•cos α) =9.8(sin22°0.26•cos22°)=…
s=v²/2a
v=sqrt(2as)=…
Respond to this Question
Similar Questions

physics
A wooden box with a mass of 10.0kg rests on a ramp that is inclined at an angle of 25 degrees to the horizontal. A rope attatched to the box runs parallel to the ramp and then passes over a frictionless pulley. A bucket with a mass … 
PHYSICS
A 100kg box is placed on a ramp. As one end of the ramp is raised, the box begins to move downward just as the angle of inclination reaches 15 degrees. What is the coefficient of static friction between box and ramp? 
Phyiscs
A wooden box with a mass of 10.0kg rests on a ramp that is inclined at angle of 25 degrees to the horizontal. A rope attached to the box runs parallel to the ramp and then passes over a frictionless pulley. A bucket with a mass of … 
physics
A box of mass 5.0 kg starting from rest slides down a 1.8 m long ramp inclined at an angle of 22.0 deg. from the horizontal. If the ramp is frictionless, how long will it take the box, starting from rest, to reach the bottom of the … 
Physics
A box of mass 54.0 kg is sitting on a ramp which makes an angle of 37.0 degrees with respect to the horizontal. The coefficient of friction between the box and the ramp is 0.21. This box is connected by a massless string over a pulley … 
Physics
A box of mass 1.50 kg is given an initial velocity of 12.5 m/s up an inclined ramp that makes an angle of 25.0o with the ground, which is horizontal. The coefficient of kinetic friction between the box and the ramp is 0.240. How long … 
Physics
A block is sitting on a rough ramp. It is found that a force of F = 200.0 N (directed up the ramp) is required to keep the box from sliding back down the ramp. The angle 𝜃 is 35.0o and the mass of the box is 150.0 kg. What … 
Physics
A box of mass 1.50 kg is given an initial velocity of 12.5 m/s up an inclined ramp that makes an angle of 25.0o with the ground, which is horizontal. The coefficient of kinetic friction between the box and the ramp is 0.240. How long … 
AP Physics
A mystery surprise box is sliding down a ramp at a constant speed. The box has a mass of 55.0kg and the ramp makes a 40.0œ angle with the horizontal. What is the coefficient of kinetic friction between the box and the ramp? 
Math
A 100kg box is placed on a ramp. As one end of the ramp is raised, the box begins to move downward just as the angle of inclination reaches 15◦. What is the coefficient of static friction between the box and the ramp?