PHY 2130 Exam 1 (Kinematics and Dynamics)

Microscopic biological structures like cells, bacteria, viruses, etc. are often measured in micrometers (one millionth of a meter) or nanometers (one billionth of a meter). If an influenza A virus is 120 nanometers long, how many micrometers is this?

120000

Is a nanometer bigger or smaller than a micrometer, and would 120 be a bigger number of micrometers or a smaller number of micrometers?

Bigger and bigger

Warren Buffet has a net worth of about $66.4 billion . If the dollar $ is treated as a unit of money, which of the following is not a correct representation of his fortune?

66.4 $ Gigga dollars

Whichoneofthefollowingpairsofunitsmaynotbeaddedtogether,even after appropriate unit conversions have been made?
A) Feet and centimeters
B) Seconds and months
C) Meters and miles
D) Kilometers and miles per hour
E) Grams and kilograms

D) Kilometers and miles per hour

Convert 28.0 m/s to mi/hr

62.6 mi/hr

Which of the following could possibly (by dimensional analysis) be part of an equation for calculating the distance traveled by a car?
A)V×T
B)A×T^2
C)Volume/Area
D)A×V×T^3 /D
E)More than one of the above

A)V×T
B)A×T^2

How many cubic millimeters ( mm ) are in one cubic meter ( m )?

E) 1,000,000,000

A person takes a trip, driving with a constant speed of 89.5 km/h, except for a 22.0-min rest stop. If the person's average speed is 77.8 km/h, find the following.
(a) How much time is spent on the trip?
(b) How far does the person travel?

A: 2.81 hr
B:219 km

A graph of position versus time for a certain particle moving along the
x-axis is shown in the figure below. Find the instantaneous velocity at
the following instants.
(a) t=1.00s (b) t=3.00s (c) t= 4.50 s (d) t = 7.50 s

A: 5m/s
B: -2.5m/s
C: 0m/s
D: 5m/s

A car accelerates uniformly from rest to a speed of 40.0 mi/h in 12.0 s.
(a) Find the distance the car travels during this time. (b) Find the constant acceleration of the car.

A: 2m
B: 1.49m/s^2

A motorist drives north for 35 minutes at 85.0 km/h and then stops for 15.0 minutes. He then continues north, traveling 130 km in 2.00 h.What is his total displacement? (b) What is his average velocity? •

(a) Displacement = 85 km/h ( 35 min) + 130 km= 180 km
(b)Totaltime=35min+15min(1h/60min)+2h= 2.83 h
V=totaldisp/totaltime=63.6km/h=17.6m/s

A tennis player moves in a straight-line path as shown in the figure below. Find her average velocity in the following time intervals.
(a)0to1.0s (b)0to4.0s (c)1.0sto 5.0 s (d) 0 to 5.0 s

A: 4 m/s
B: -0.5 m/s
C: -1 m/s
D: 0

A person takes a trip, driving with a constant speed of 89.5 km/h, except for a 22.0-min rest stop. If the person's average speed is 77.8 km/h, find the following.
(a) How much time is spent on the trip?
(b) How far does the person travel?

A: 2.8 hr
B: 219 km

Consider two situations:
A skydiver who is falling with constant velocity
A book that is sitting on a table, completely stationary.

Skydiver: forces act but zero net force
Book: Forces act, but zero net force

The net force on a moving object suddenly becomes zero. The object then

continues at a constant velocity

A mosquito flies head-on into a semi truck traveling at 60mph. Which is true during the collision?
A) The mosquito exerts more force on the truck than the truck exerts on the mosquito
B) The truck exerts more force on the mosquito than the mosquito exerts on the truck
C) The mosquito exerts the same force on the truck as the truck exerts on the mosquito
D) The truck exerts a force on the mosquito but the mosquito does not exert a force on the truck
E) The mosquito exerts a force on the truck but the truck does not exert a force on the mosquito

C) The mosquito exerts the same force on the truck as the truck exerts on the mosquito

A mosquito flies head-on into a semi truck traveling at 60 . Which is true during the collision?
A) The mosquito experiences a larger acceleration
B) The truck experiences a larger acceleration
C) The mosquito and the truck experience the same acceleration

A) The mosquito experiences a larger acceleration

A force of magnitude pushes block X with mass 2 , which in turn pushes block Y with mass as shown. The blocks are accelerated across a horizontal, frictionless surface. What is the magnitude of the force that block Y exerts on block X?
A) F/3
B) F/2
C) F
D) 2F
E) F3

A: F/3

Two masses are tied together by a rope that's looped over a pulley. The rope exerts the same upward force on both masses. The masses are moving in the direction shown and are slowing down. Which mass is heavier?
A) Mass A
B) Mass B
C) Neither, they're equal
D) There's no way to tell

A) Mass A

A book is at rest on a table. There is an upward force on the book from the table, F(t-b) Then, a person puts their hand on the book and presses down. What happens to the size of F (t-b)?
A) It increases
B) It decreases
C) It stays the same
D) There's no way to tell

A) It increases

A book is at rest on a table. The upward normal force on the book from the table is _____ the downward gravitational force on the book. (Note: we are comparing only the magnitudes.)
A) Less than
B) Equal to
C) Greater than
D) There's no way to tell

B) Equal to

A book is at rest on a table. Then, a person puts their hand on the book and presses down. The upward normal force on the book from the table is _____ the downward gravitational force on the book. (Note: we are comparing only the magnitudes.)
A) Less than
B) Equal to
C) Greater than
D) There's no way to tell

C) Greater than

Two ropes of different thickness are joined together. A person pulls on the end of the thinner rope with a force . The person holding the thicker rope feels the rope pulling with a force that is
A) Bigger than
B) Equal to
C) Less than
D) There's not enough information to tell

B) Equal to

All three 50 blocks are at rest and experience the same gravitational force. The tension in rope 2 is
A) Greater than the tension in rope 1
B) Equal to the tension in rope 1
C) Less than the tension in rope 1

B) Equal to the tension in rope 1

A box is being pulled to the right at an increasing speed by a rope that angles upward. The surface is frictionless. Consider the following statements:
1) The normal force on the box is equal to
2) The acceleration of the box is equal to |T|/m Which of the above statements is true?
A)Both 1 and 2 are true
B) Only 1 is true
C) Only 2 is true
D) Neither 1 nor 2 is true

D) Neither 1 nor 2 is true

A ball is thrown directly down with an initial velocity of 8m/s from a height of 30 m. After what time interval does it strike the ground?

1.79 s

A baseball is hit so that it travels straight upward after being struck by the bat. A fan observes that it takes 3.00 s for the ball to reach its maximum height. A) Find the ball's initial velocity. B) Find the height it reaches.

A) 29.4 m/s
B) 44.1 m

A baseball is thrown at θ= 37⁰ at 20 m/s. A) Calculate the maximum height. B) The time to reach the maximum height and the maximum horizontal distance.

A)
B) 1.32 s/ 42.24 m

An athlete executed a long jump by leaving the ground at 30⁰ and travels 8.9 m. What is his take off speed?

v= 10m/s