Transcript Chapter 4 Review

Chapter 4 Review
Question
• What is the SI unit of force?
Answer
• Newton
Question
• A 1850 kg car is moving to the right at a
constant speed of 1.44 m/s. What is the net
force on the car?
Answer
• Zero
Question
• What acceleration would you give a 24.3 kg
box if you push it horizontally with a net force
of 85.5 N?
Answer
• 3.52 m/s2
Question
• What net force is required to give a 25 kg
suitcase an acceleration of 2.2 m/s2 to the
right?
Answer
• 55 N to the right
Question
• Find the normal force acting on 5.5 kg laundry
basket that is at rest on a ramp inclined at 12⁰
above the horizontal.
Answer
• 54 N
Question
• Which is usually greater, the maximum force
of static friction or the force of kinetic friction?
Answer
• Maximum force due to static friction
Question
• A 95 kg clock initially at rest on a horizontal
floor requires a 650 N horizontal force to set it
in motion. After the clock is in motion, a
horizontal force of 560 N keeps it moving with
a constant velocity. Find µs and µk between
the clock and the floor. (1 point each)
Answer
• µs = 0.70
• µk = 0.60
Question
• A box slides down a 30.0⁰ ramp with an
acceleration of 1.20 m/s2. Determine the
coefficient of kinetic friction between the box
and the ramp. Be careful with direction!
Answer
• 0.436
Question
• A clerk moves a box of cans down an aisle by
pulling on a strap attached to the box. The
clerk pulls with a force of 185.0 N at an angle
of 25.0⁰ with the horizontal. The box has a
mass of 35.0 kg, and the coefficient of kinetic
friction between the box and the floor is
0.450. Find the acceleration of the box.
Answer
• 1.4 m/s2 down the aisle
Question
• What are 2 possible states of motion an object
might be experiencing if it is in equilibrium?
Be specific! (1 point each)
Answer
• At rest
• constant speed in a straight line
Question
• A smart car and a hummer collide. Which car
experiences the greater force?
Answer
• Force is equal on both cars
Question
• A girl on a sled coasts down a hill. Her speed is
7.0 m/s when she reaches level ground at the
bottom. The coefficient of kinetic friction
between the sled’s runners and the hard, icy
snow is 0.050, and the girl and the sled
together weigh 645 N. How far does the sled
travel on level ground before coming to a rest?
Answer
• 49 m
Question
• In what direction does the normal force
ALWAYS act?
Answer
• Perpendicular to the contact surface
Question
Question
• Find the weight of the picture.
Answer
• 42.4 N
Question
• Justin Bieber runs into CeeLo Green and they
collide. Who has the greater acceleration and
why?
Answer
• Justin Bieber because he has a smaller mass
Question
• The sign has a mass of 10 kg. Find the tension
in each cable.
Answer
• 56.6 N
Question
• A bag of sugar has a mass of 2.26 kg. What is
its weight in newtons on the moon, where the
acceleration due to gravity is one-sixth that of
Earth?
Answer
• 3.7 N
Question
• Name one example of a field force
Answer
• Gravitational force, magnetism
Question
• A freight train has a mass of 1.5 x 107 kg. If the
locomotive can exert a constant pull of 7.5 x
105 N, how long would it take to increase the
speed of the train from rest to 85 km/h?
Answer
• 470 s
Question
• What is the tendency of objects to NOT
accelerate called?
Answer
• inertia
Question
• What is the vector sum of all external forces
acting on an object called?
Answer
• Net force
Question
• What is the SI unit of mass?
Answer
• kilogram
Question
• What is the mass of a 63 kg object on Venus
where the acceleration due to gravity is 5.8
m/s²?
Answer
• 63 kg silly!