Latihan Soal Dinamika Gesekan Kelas XI SMAK 1 2009

SMAK 1 PENABUR Jakarta Nama :__________________Fisika kelas XI semester 1 2009 Kls/No:__________/_______Joshua Untung W. Iman dapat membawa kita ke sorga, tetapi kasih sayang diantara sesama

yang membawa sorga ke dalam hati kita

Practice Makes PERFECT !

DINAMIKA (HUKUM NEWTON)

1 A downhill skier starts from rest down a 37° slope for which μk = 0.1. (a) How long does it take to reach

72 km/h ?

(b) What is the distance covered? Ignore air resistance.

2 (I) A block is released at the top of a 20° incline. Determine the coefficient of kinetic friction given that it slides 2.4 m in 3 s.

3 (II) The minimum stopping distance for a car from an initial 90 km/h is 60 m on level ground. What is the stopping distance when it moves (a) down a 10° incline;

(b) up a 10° incline? Assume that the initial speed and the surface are unchanged.

4 (I) Two blocks are connected as shown in Figure beside and move at constant velocity (the 5 kg-block moves down the incline). Find: (a) the coefficient of kinetic friction

assuming it is the same for both blocks;

(b) the tension in the rope.

5 (I) A 5-kg block is on a 37° incline for which μk = 0.1. It is acted on by a hori-zontal force of 25 N, as in Figure beside. (a) What is the acceleration of the block

if it is moving up the incline?

(b) If its initial speed is 6 m/s up the incline, how far does it travel in 2 s?

Bab 5: Dinamika (Hukum Newton) page 1 of 3



6 (II) Two blocks with equal masses m1 = m2 = 5 kg are connected via a pulley, as shown in Figure beside. Take μk = 0.25. Find the acceleration given that (a) m1 is moving down,

(b) m1 is moving up.

(c) If m2 = 6 kg, for what values of m1

will the pair move at constant speed?

7 (II) In Figue beside, when m1 = 3 kg, its acceleration is 0.6 m/s2

• When m1 = 4 kg, its acceleration is 1.6 m/s2

• Find m2

and the frictional force acting on it. (Note that m1 and m2 do not have the same acceleration.)

8 (II) Block A of mass mA= 2 kg is on the front face of cart B of mass mB = 3 kg. A force of 60 N acts on mB. What is the minimum coefficient of friction needed for mA not to slide down?

9 (II) The horizontal force F in Figure beside accelerates the 4-kg block at 1 m/s2 to the left. Assume μk = 0.5. Given that the 5 kg block moves up the slope find (a) the value of F, and

(b) the tension in the rope.

(c) If F = 10 N and the 5-kg block moves down the slope, what is the acceleration?





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Latihan Soal Dinamika Gesekan Kelas XI SMAK 1 2009