Physics 105

Chapter 2: Describing Motion in One Dimension

A car travels 40 kilometers at an average speed of 80 km/h and then travels 
40 kilometers at an average speed of 40 km/h. The average speed (in km/h) of 
the car for this 80 km trip is:

The vectors 𝑎⃗ , 𝑏⃗⃗ , and 𝑐⃗ are related by 𝑐⃗ = 𝑎⃗ − 𝑏⃗⃗ . Which diagram below 
illustrates this relationship?<img src=""/>

Two blocks weighing 250 N and 350 N respectively, are connected by a string 
that passes over a massless pulley as shown. The tension (in N) in the string is :

&nbsp;A 5.0-kg block is resting on a horizontal plank. The coefficient of static friction 
is 0.50 and the coefficient of kinetic friction is 0.40. After one end of the plank is raised so the plank makes an angle of 25 with the horizontal, the force of 
friction (in N) is:

A 5.0-kg block is on an incline that makes an angle 30 with the horizontal. If 
the coefficient of static friction is 0.50, the minimum force (in N) that can be 
applied parallel to the plane to hold the block at rest is:

A 5.0-kg block is on an incline that makes an angle 30 with the horizontal. If 
the coefficient of static friction is 0.5, the maximum force (in N) that can be 
applied parallel to the plane without moving the block is:

A 4.00-kg block rests between the floor and a 3.00-kg block as shown in the 
figure. The 3.00-kg block is tied to a wall by a horizontal rope. If the coefficient 
of static friction is 0.800 between each pair of surfaces in contact, what 
horizontal force F (in N) must be applied to the 4.00-kg block to make it move?

A 4.00-kg block rests on a 30.0° incline as shown in the figure. The 
coefficients of static friction and kinetic friction between the block and the 
incline are 0.700 and 0.500 respectively. The magnitude of the force F (in N) that 
must act on the block to start it moving up the incline is:

1 A particle starts from rest at time t = 0.00 s and moves in the +x direction 
with constant acceleration. If the particle travels 6.0 m during the time t = 1.00 s 
to t = 2.00 s, find its acceleration (in m/s2)

Block A of mass 5.0 kg and block X are attached to a rope which passes over 
a pulley, as shown in the figure. An 80-N force P is applied horizontally to block 
A, keeping it in contact with a rough vertical face. The coefficients of static and 
kinetic friction between the wall and block A are μs = 0.40 and μk = 0.30. The 
pulley is light and frictionless. The mass of block X is adjusted until block A 
moves upward with an acceleration of 1.6 m/s 2 . What is the mass (in kg) of 
block X?

Block A, with mass mA, is initially at rest on a horizontal floor. Block B, with 
mass mB, is initially at rest on the horizontal top surface of A. The coefficient of 
static friction between the two blocks is µ s. Block A is pulled with a horizontal 
force. It begins to slide out from under B if the force is greater than:

A rope pulls on the lower block in the figure with a tension force of 20 N. The 
coefficient of kinetic friction between the lower block and the surface is 0.16. 
The coefficient of kinetic friction between the lower block and the upper block is 
also 0.16. The pulley has no appreciable mass or friction. What is the 
acceleration (in m/s2 ) of the 2.0 kg block?

Two identical masses M1 and M2 (M1 = M2 = M) are dropped from rest from 
different heights to the ground (neglect air resistance). M1 takes time t to reach 
the ground, while M2 takes time 2t to reach the ground. If M1 is dropped from 
height H1 and M2 is dropped from height H2, find the ratio H1/H2.

Two particles are thrown from the top of a building with the same initial 
speed at the same instant of time. Particle(1) is thrown up and particle(2) is 
thrown down (Neglect air resistance). Comparing their final speeds just before 
they hit the ground, one of the following statements is CORRECT:

The final speed of both particles will be exactly the same.

The two particles arrive the ground at the same time.

The final speed of Particle(1) is higher.

Particle(1) arrives the ground earlier than Particle(2).

The final speed of Particle(2) is higher.

A 2-kg Physiology textbook hangs vertically from a cable in an elevator. If the 
tension in the cable is 16 N, the acceleration (in m/s2) of the elevator is: [Hint: 
Take the upward direction as positive (+)]

A 4-kg block slides down a hill that is inclined at 20o with respect to the 
horizontal with an acceleration 1.1 m/s2 directed up the hill. The coefficient of 
kinetic friction between the block and the hill is:

As shown, four masses connected with wires, are hanging from a ceiling. The 
masses are: m1 = 5.5 kg, m2 = 2.4 kg, m3 = 9.9 kg, and m4 = 3.6 kg. The tension 
(in N) in the wire connecting masses m1 and m2 is approximately:

&nbsp;The three blocks (A, B, and C) shown next do rest on the table. The weight 
for block A is 1 N, the weight of block B is 2 N, and the weight of block C is 5 N. 
The magnitude of the force (in N) exerted by block C on block B is :

The box shown rests on a rough horizontal surface, where the coefficients of 
static and kinetic friction between the box and the surface are 0.59 and 0.41 
respectively. The two forces shown are then applied on the box. The box will be 
on the verge of start moving when the horizontal force F (in N) has the 
magnitude of:

Three masses (M, 15 kg, and 10 kg) are connected by massless wires over a 
massless frictionless pulley as shown in the figure. If the tension in the wire B 
connecting the 10.0 kg and 15.0 kg masses is 133 N, find the tension (in N) in 
wire A.

As shown, the force F is pushing horizontally on the wedge m which is placed 
on the incline surface. The coefficient of 
kinetic friction between the wedge and the 
incline is 0.16. Knowing that F = 300 N, m = 34-kg, 
and θ = 20o, the magnitude of the wedge’s 
acceleration (in m/s2) along the incline is:

As shown, the force P, of magnitude 70 N, is applied to a 3-kg block to 
enforce it to accelerate across the ceiling. The coefficient of kinetic friction 
between the block and the ceiling is 0.26. Given that the angle θ is 72o, the 
magnitude of the block’s acceleration (in m/s2) is:

As shown, the two blocks, m1 and m2, are connected by a wire of negligible 
mass. The force F, of magnitude 35 N, is applied to block m2. The coefficient of 
kinetic friction between each block and the horizontal surface is 0.26. Given that 
m1 = 2-kg, m2 = 1-kg, and the angle θ = 29o, the tension (in N) in the wire is:

As shown, the two boxes, mc (3-kg) and mw (5-kg), are accelerated along a 
rough horizontal track. The force F (20 N) acts horizontally upon the left side of 
box mc. If the magnitude of the kinetic frictional forces on the mc and mw boxes 
are 5 N and 7.5 N respectively, what is the magnitude of the force (in N) exerted 
by mc box on mw box?

In the diagram, 𝐴⃗ has magnitude 12 m and 𝐵⃗⃗ has 
magnitude 8 m. The x component (in m) of 𝐴⃗ + 𝐵⃗⃗ is: