How do you solve these two physics problems?

Question

Question 1:An extremely light, drivable car with a mass of only 9.50kg was built in London. Suppose that the wheels of the car are locked, so that the car no longer rolls. If the car is pushed up a 30.0 degree slope by an applied force of 80.0N, the net acceleration of the car is 1.64 m/s^2. What is the coefficient of kinetic friction between the car and the incline?

Question 2:Cleopatra's Needle, an obelisk given by the Egyptian government to Great Britain in the nineteenth century, is 20+ m tall and has a mass of about 1.89 * 10^5 kg. Suppose the monument is lowered onto its side and dragged horizontally to a new location. An applied force of 7.6 * 10^5 N is exerted on the monument, so that its net acceleration is 0.11m/s^2. What is the magnitude of the frictional force?

Can you show some work so that I can figure out how you did the problem?

Answer 1

For a body in constant acceleration, the sum of all forces is equal to m*a

Prob 1)

Convert the mass to weight:

9.5kg = 93.163 N

Draw an x,y coordinate system along the incline, where the x coordinate is parallel to the slope and the y is perpendicular.

SUM Fx = 93.163 * sin 30 - u*(80) = 1.64*9.5
where u is the coefficient of kinetic friction.

u = (93.163*sin 30 - 1.64*9.5)/80
u = 0.3885

Prob 2)

1.89*10^5kg = 1853456.855412 N

u = (7.6*10^5 - 0.11*1.89*10^5)/1853456.855412
u = 0.3988

Answer 2

Use Conservation of Momentum, i.e. p_f=p_i. p=mv, m1 is mass a million & m2 is mass 2 For the 1st undertaking, you've m1v1_i+m2v2_i=(m1+m2)vf. because of the fact m2 is at relax, the 2nd term drops out. For the 2nd undertaking, that's m1v1_i+m2v2_i=m1v1_f+m2v2_f. back, m2 is at relax, so the 2nd term drops out. The 0.33 term additionally drops out it says the outstanding speed of the outstanding mass is 0 m/s. something could be user-friendly.

Answer 3

Everything can be solved by the simple equation:

F=ma

Start with that.

(I can solve this, but I would be doing your work for you, wouldn't I?)