Old Exam.
Question Chapter 6 (Dr. Gondal Phys. 101)
T082
Q#18:
A 5 kg block is placed on top of a 10 kg block which is lying on a frictionless horizontal surface, as shown in
Fig. 4. A horizontal force F of 60 N is applied to the 10 kg block. Find the static frictional force on 5 kg block from the 10 kg
block such that the 5 kg block does not slip. A) 20 N to the right
Q19
. A crate is sliding down an incline that is 35◦ above the horizontal. If the coefficient of kinetic friction is 0.4 the
acceleration of the crate is: A) 2.4 m/s2
Q20
. An automobile moves on a level horizontal road in a circle of radius 30 m. The coefficient of static friction between
tires and road is 0.5 . The maximum speed with which this car can travel round this curve without sliding is: A) 12 m/s
Fig. 4, T082
Fg. 4, T081
T081
:
Q19.:
A 1.0 kg block, attached to the end of a string of length 2.0 m, swings in a vertical circle. When the block is at
its highest point, its speed is 5.0 m/s. What is the magnitude of the tension in the string at that point? A)
2.7 N
Q20:
A block of mass m = 10 kg is pushed up a rough 30
o
inclined plane by a force F parallel to the incline as
shown in Figure 4. The coefficient of kinetic friction between the block and the plane is 0.4. Find the magnitude of
the force F when the block is moving up at constant velocity. (Ans: 83
N)
T072: Q15
.A constant horizontal force of 36 N is acting on a block of mass 4.0 kg, another block of mass 2.0 kg sits
on the 4.0 kg block. The 4.0 kg block moves on a frictionless horizontal floor. Find the magnitude of the frictional
force maintaining the 2.0 kg block in its position above the 4.0 kg block during the motion.(Ans: 12 N)
Q18.
In Fig. 4, a boy is dragging a box (mass =8.0 kg) attached to a string. The box is moving
horizontally with an acceleration a = 2.0 m/s
2
.
If the frictional force is 12 N, calculate the applied
force F at an angle θ=60° (Ans: 56 N)
Q19
.At what angle should the circular roadway of 50 m radius, be banked to allow cars to round the curve without
slipping at 12 m/s? (Ignore friction)(Ans: 16°)
Q20.
A 1000 kg airplane moves in straight horizontal flight at constant speed. The force of air resistance is 1800 N.
The net force on the plane is: (Ans: zero)
T071:
Q17.
: A 5.0 kg block is moving with constant velocity down a rough incline plane. The coefficients of static
and kinetic friction between the block and the incline are 0.25 and 0.20, respectively.
What is the inclination angle
of the incline plane? (Ans: 11°)
Q18.
A car rounds a flat curved road (radius = 92 m) at a speed of 26 m/s and is on the verge of sliding at this speed.
What is
the coefficient of static friction between the tires of the car and the road? (Ans:
0.75)
Q19.:
A box of mass 40.0 kg is pushed across a rough flat floor at the constant speed of 1.50 m/s.
When the force is
removed, the box slides a further distance of 1.20 m before coming to rest. Calculate the friction force acting on the box
when it slides.(Ans:
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '11
 LEE
 Force, Friction, racing car

Click to edit the document details