grade 11 physics problems. 10 points.?
i missed the whole week we learned how to do all these question, teacha' tried explaining them but he dint have enough time. anyway, i gotta know how to do these, some help would be awesome haaha
1. The coefficient between hard rubber and normal street pavement is about 0.8. On how steep a hill (maximum angle) can you leave a car parked?
2. The piece of macheniery shown in figure below, in which two masses are suspended over a pulley, is called an Atwood's machine. Block A has a mass of 1.2kg and block B has a mass of 3.2kg. Assuming the pulley is massless and frictionless, and that the cord is massless and doesn't strech, calculate:
(a) the acceleration of the system
(b) the tension in the cord
3. A woman i know weights 600N (i think its like 135 pounds)
(a) should I:
tie her down so that she doesn't blow away in the wind; or reinforce the floor under her; or compliment her on her svelt appearance?
Give a justification and include the woman's mass in your answer.
Your answer to the following will depend on the fact that a bathroom scale measures Normal force and not weight. Keep that in mind as you answer these questions.
(b) the elevator ascends at a constant speed of 5 m/s;
(c) the elevator ascends uniform acceleration 3 m/s^2
(d) the elevator descends at a uniform acceleration of 3 m/s^2.
4. What is the average force exerted by a shotputter on a 7.0 kg shot if the shot is moved through a distance of 2.9 m and is released with a speed of 13 m/s?
Comments
1. F=0.8N
On a ramp, normal=9.8mcosx
Acceleration force=9.8msinx
F=0.8*9.8*mcosx
9.8msinx=0.8*9.8mcosx
9.8sinx=7.84cosx
x=0.6747 radians
2. 2*9.8=(3.2+1.2)a
a=4.45 m/s^2
3.2*9.8 - T = 3.2 * 4.67
T=17.996 N
3. Mass: 600/9.8=61 kg, I'd complement her I guess
R=ma
N - 600=61*0
N=600 N
R=ma
N - 600= 61*3
N=783 N
R=ma
N - 600=61*-3
N=417 N
4. acceleration: 13/2.9=4.48 m/s^2
R=7.0*4.48
R=31.4 N
Hope that helps
better refer krishna's by p.m agarwal