Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

1. 3 blocks, a, b, and c of different masses, start from rest and slide down the

ID: 2151790 • Letter: 1

Question

1. 3 blocks, a, b, and c of different masses, start from rest and slide down the three frictionless, stationary ramps shown below. Blaock a and block b both have mass 0.5 kg each, while block c has a mass of 1 kg. Which block has the greatest speed at the bottom of the ramp? *Air-resistance negligible (Angle of the ramps: 25 deg, 45 deg, 60 deg.)

Answer : All three blocks have the same spd. at the bottom of the ramp. Why?

2.A car of mass 1550kg starts from rest and reaches a spd. of 26.m/s in 7.10 s. What is the average power needed to accomplish this?

5. A 5.0 kg mass is subject to a force F= (4.79 i + 3.79 j - 2.09k) N. Find the work done by the force if it causes a displacement of the mass by r= (4.25 i - 3.69 j - 2.45 k) m.

7. The irregular hill has a vertical drop of 25m. How much work does the gravitational force do on a 70.0-kg skier traversing this run? The shape of the hill can be approximated by the equation y= ax^3, where y is the height in meters above the ground level. The value of a is -1.5 m^-2, and both x and y are equal to 0 m at the base of the hill...

8. Which of the following is an example of a non-conservative force?

a. the gravitational force.
b. the spring force.
the force due to friction
d. all of the above are non-conservative forces.
e. both choices b and c are examples of non-conservative forces

9. A 1.0 kg block is released from point A, as shown in the figure(height= 3.00 m). The track is frictionless except for the portion between points B and C of a length 6.00 m. The coefficient of kinetic friction between the block and the rough surface is 0.4. The block travels down the track, hits a spring and compresses the spring 10 cm from its equilibrium position before coming to rest momentarily. What is the spring constant?

answer: 1180 N/m.

Explanation / Answer

1. speed = sqrt(2gh) is independent of mass and angle 2. 1/2 * mv^2 /time 5. work = F.r