Physics Midterm

Rank the following mass measurements from smallest to largest: 11.6mg, 1021 ug, .000006kg, .31mg

.31mg, 1021ug, .000006kg, 11.6mg

You convert the speed limit of an expressway given in miles per hour into meters per second and obtain the value 1.5 m/s. Is this calculation likely to be correct?

1.5m/s is too slow for an automobile

A water tank has a mass of 3.64kg when it is empty and a mass of 51.8kg when it is filled to a certain level. What is the mass of the water in the tank?

51.8-3.64 48.2kg

A car moves 65km due east, then 45km due west. What is its total displacement?

65km - 45km = 20km d=2.0x10km, east

A force of 40 N accelerates a 5kg black at 6m/s^2 along a horizontal surface. How large is the frictional force? What is the coefficient of friction?

F=f- ma =40N-(5kg)(6m/s^2) =1.0x10^1N F=ukFn=umg uk=F/mg=10N/(5kg)(9.81) =.20

Your new motorcycle weighs 2450N. what is its mass in kg?

F=mg m=w/g -2450/-9.81 m=2.50x10^2g

A ship leaves its home port expecting to travel to a port 500.0km due south. Before it moves even 1km, a severe storm blows it 100km due east. How far is the ship from its destination? In what direction must it travel to reach its destination?

R^2= 100^2 +500^2 R=509.9 tan@=500/100 tan@=5 @=78.69degrees d= 509.9km, 78.69, south of west

You walk 30m south and 30m east. Find the magnitude and direction of the resultant displacement both graphically and algebraically.

R^2= 30^2 + 30^2 R=40m tan@=30/30 tan@=1 R=40m, 315 degress

what is your weight in newtons?

W=gm =(9.80)m

How does a vector quantity differ from a scalar quantity?

a vector quantity has both magnitude and direction a scalar has only magnitude

Convert each of the following measurements to meters. a. 42.3cm b. 6.2pm c. 21km d. .023mm e. 214um f. 570nm

a. .0423m b. 6.2x10^-12m c. 2.1x10^4m d. 2.3x10^-5m e. 2.14x10^-4m f. 5.70x10^-7m

State the number of sigfig digits in each of the following measurements. a. 0.00003m b. 64.01fm c. 80.001m d. 0.720ug

a. 1 b. 4 c. 5 d. 3

Multiply or divide as indicated. a. (6.2x10^18m)(4.7x10^-10m) b. (5.6x10^-7m)/(2.8x10^-12m) c. (8.1x10^-4km)(1.6x10^-3km) d. (6.5x10^5kg)/(3.4x10^3m^3)

a. 2.9x10^9m^2 b. 2.0x10^5m^2 c. 1.3x10^-6km^2 d. 1.9x10^2kgm^3

State the number of sigfig digits in each of the following measurements. a. 2.40x10^6kg b. 6x10^8kg c. 4.07x10^16m

a. 3 b. 1 c. 3

Add or subtract as indicated. a. 16.2m + 5.008m + 13.48m b. 5.006m + 12.0077m + 8.0084m c. 78.05cm^2 - 32.046cm^2 d. 15.07kg - 12.0kg

a. 34.7m b. 25.022m c. 46.00cm^2 d. 3.1kg

Express the following numbers in scientific notation a. 5000000000000m b. .000000000166m c. 2003000000m d. .0000001030m

a. 5x10^12m b. 1.66x10^-10m c. 2.003x10^9m d. 1.030x10^-7m

Add or subtract as indicated. a. 5.80x10^9s + 3.20x10^8s b. 4.87x10^-6m - 1.93x10^-6m c. 3.14x10^-5kg + 9.36x10^-5kg d. 8.12x10^7g - 6.20x10^6g

a. 6.12x10^9s b. 2.94x10^-6m c. 1.25x10^-4kg d. 7.50x10^7g

Using a calculator, Chris obtained the following results. Give the answer to each operation using the correct number of sigfig. a. 5.32mm + 2.1mm = 7.4200000mm b. 13.597m x 3.56m = 49.62905m^2 c. 83.2kg - 12.804 kg = 70.3960000kg

a. 7.4mm b. 49.6m^2 c. 70.4kg

You row a boat perpendicular to the shore of a river that flows at 3m/s. the velocity of your boat is 4m/s relative to the water. a. What is the velocity of your boat relative to the shore? b. What is the component of your velocity parallel to the shore? Perpendicular to it?

a. R= (3)^2 + (4)^2 R=5m/s tan@=4/m=1.33 2=53 degrees with the shore b.3m/s 4m/s

A descent vehicle landing on Mars of 5.5m/s. At the same time, it has a horizontal velocity of 3.5m/s. a. At what speed does the vehicle move along its descent path? b. At what angle with the vertical is this path?

a. R^2=(5.5)^2 + (3.5)^2 v=R=6.5m/s b. tan@=3.5/3.5=.64 @=32degrees

Give the name for each multiple of the meter a. 1/100m b. 1/1000m c. 1000m

a. centimeter b. millimeter c. kilometer

A bag is dropped from a hovering helicopter. When the bag has fallen 2s, a. what is the bag's velocity? b. How far has the bag fallen?

a.v=vi+at =0m/s + (-9.81)(2s) v==2.0x10^1m/s b. d=vit + (1/2)(a)t^2 d=0 + (1/2)(-9.81)(2s)^2 d= -2.0x10^1m

Find the uniform acceleration that causes a car's velocity to change from 32m/s to 96m/s in an 8 sec period.

a=(96m/s-32m/s)/(8s) a= 8m/s^2

A rectangular floor has a length of 15.72m and a width of 4.40m. Calculate the area of the floor.

a=2l+2w 69.2m^2

How are velocity and acceleration related?

acceleration is the change in velocity divided by the time interval in which it occurs. it is the rate of change of velocity

You ride your bike for 1.5h at an average velocity of 10km/h, then for 30 min at 15km/h. What is your average velocity?

d1=(10km/h)(1.5h)=15km d2=(15km/h)(.5h)=7.5km (15km+7.5km)/(1.5h + .5h) v=10km/h

A bike accelerates from 0m/s to 5m/s in 4.5s, then continues at this constant speed for another 4.5s. What is the total distance traveled by the bike?

d=((0m/s + 5m/s)/2)4.5s d=11.25m d=vt d=(5m/s)(4.5s) d=22.5m d= 11.25m + 22.5m d=34m

A car is traveling 20m/s when the driver sees a child standing in the road. He takes .8s to react, then steps on the brakes and slows at 7m/s^s. How far does the car go before it stops?

d=vif + (1/2)at^2 d=(20m/s)(.8s) + (1/2)(-7m/s^2)(.8)^2 d=13.76m vf^2=vi^2 +2ad 0=20^2 + 2(7)d d=28.57 d=13.76+28.57 d=42.33m

A bike accelerates from 0m/s to 4.0m/s in 4s. What distance does it travel?

d=vt d=(4-0)(4) d=16m

A bike travels at a constant speed of 4.0m/s for 5s. how far does it go?

d=vt d=(4m/s)(5s) d=20m

How are base units and derived units related?

derived units are combinations of the base units

You and a friend each drive 50km. You travel at 90km/h; your friend travels at 95km/h. How long will your friend wait for you at the end of the trip?

friend: 50km/95km/h = .526 hr = 31.6min you: 50km/90km/h= .555 hr = 33.3min so your friend waits 1.7 minutes

what to round to in + and -

last digit

A hiker leaves camp and, using a compass, walks 4km E, then 6km S, 3km E, 5km N, 10km W, 8km N, and finally 3km S. At the end of three days, the hiker is lost. By drawing a diagram, compute how far the hiker is from camp and which direction should be taken to get back to camp..

north: -6+5+8-3=4km east: 4+3-10=-3km R^2=(-3)^2 + (4)^2 R=5km tan@=4/3=1.33 @=53 degrees R=5km, 53 degrees south of east

what to round to in x and /

number of sigfig

List the common SI base units

seconds, meters, and kilograms

Why is SI important?

the international system of units or SI allows scientists all over the world to make measurements in the same system. thus scientists know exactly what is meant by measurements made by other scientists.

During a baseball game, a batter hits a high pop-up. If the ball remains in the air for 6s, how high does it rise? Hint: Calculate the height using the second half of the trajectory.

time to fall is 3s d=vt+ (1/2)at^2 =0 + (1/2)(-9.81)(3)^2 d= -44m the ball rises 44m, the same distance it falls

Light from the sun reaches Earth in 8.3min. The velocity of light in 3.00x10^8m/s. How far is Earth from the sun?

time=8.3min=498 sec=5.0x10^2s d=vt d=(3.00x10^8m/s)(5.0x10^2s) d=1.5x10^11m

A weather station releases a balloon that rises at a constant 15m/s relative to the air, but there is a wind blowing at 6.5m/s toward the west. What are the magnitude and direction of the velocity of the balloon?

v= (6.5)^2 + (15)^2 =16m/s tan@=6.5/15=.43 @=23 degrees v=16m/s, 113 degrees

You are piloting a small plane, and you want to reach an airport 450km due south in 3 hours. A wind is blowing from the west at 50km. What heading and airspeed should you choose to reach your destination in time?

v=d/t v=450km/3h=150km/h v=((150km/h)^2 =(50km/h)^2)^1/2 v=160km/h @=tan^-1(50/150) @=18 degrees west of south

A car with a velocity of 22m/s is accelerated uniformly at the of 1.6m/s^2 for 6.8s. What is its final velocity?

v=vi+at v=22m/s +(1.6)(6.8s) v=33m/s

You throw a ball downward from a window at a speed of 2m/s. The ball accelerates at 9.8m/s^2. How fast is it moving when it hits the sidewalk 2.5m below?

vf^2=(-2.0m/s)^2 + 2(-9.81)(0-2.5) vf=53.05m/s

A student drops a ball from a window 3.5m above the sidewalk. The ball accelerates at 9.81m/s^2. How fast is it moving when it hits the sidewalk?

vf^2=vi^2 + 2a(df-di) vf^2=0 + 2(9.81)(3.5-0) V=8.28m/s