A 40 kg box has an initial velocity of 6 m/s down a 30-degree inclined plane at an initial height of 4 meters. The coefficient of friction between the box and the ground is 0.4. [a] Calculate the box’s velocity when it reaches the bottom of the inclined plane.

1200-kg car is coasting down a 30° hill as shown in Fig. 6-4. At a time when the car's speed is 12 m/s, the driver applies the brakes. What constant force F (parallel to the road) must result if the car is to stop after traveling 100 m?

0:19 Q33.pdf An automobile weighing 5500 lb is driven down a 5° incline at a speed of 60 mi/h when the brakes are applied, causing a constant total braking force (applied by the road on the tires) of 1700 lb. Determine the distance trav- eled by the automobile as it comes to a stop. 5°

(2) Four dollies (A, B, C and D) on a plane are connected by three ropes, ropes 1, 2 and 3, as shown in the diagram. The rightmost dolly is powered and pulled in the overall rightward direction by a force of magnitude F. The 4 dollies accelerate with the same acceleration. The friction between the ground and the dolly is negligible. At this point, answer the following questions. The rope does not stretch and the mass of the rope is neglected.< 台車D m4 ロープ3 m3 台車C ロープ2 m2 台車B ロープ1 m1 台車A F At this point, increase the strength of the F. Which rope breaks first. The ropes are all of the same strength.< (3) With all four trolleys of the same mass m, establish the equation of motion for each trolley in the right-hand direction of the paper. The right direction of the paper is the x- direction and only the equation of motion in the x-direction is derived. Also, include the tension of the rope between A and B as the tension of the rope between B and C and the tension of the rope between C and…

. (II) A skier moves down a 12° slope at constant speed. Whatcan you say about the coefficient of friction  μk?, Assume thespeed is low enough that air resistance can be ignored.

You went on a drive late at night after having a fun party with the member of your company when you accidentally hit another car. The investigator observes a skid marks 25m long left by your 1500kg car. Your car skidded to stop on a concrete highway having a coefficient of kinetic friction with the tires of 0.80. Estimate your car's speed at the beginning of the skid?

To make an object start moving on a surface with friction, will it usually require more, less or the same amount of force as to keep it moving on the same surface?

*15-52. The free-rolling ramp has a mass of 40 kg. A 10-kg crate is released from rest at A and slides down 3.5 m to point B. If the surface of the ramp is smooth, determine the ramp's speed when the crate reaches B. Also, what is the velocity of the crate? 3.5 m 30° 00.

79. ssm A student is skateboarding down a ramp that is 6.0 m long and inclined at 18° with respect to the horizontal. The initial speed of the skateboarder at the top of the ramp is 2.6 m/s. Neglect friction and find the speed at the bottom of the ramp.