help plssss... answer college physics problem...?

Question

1. a meter is about 3.28 feet and a hectare is 10,000 square meters. find the area of a rectangular lot whose length is 2.500 feet and whose width is 1,750 feet in (a) square ft (b) square meters (c) hectares.

2. the speed of light in free space is equal to 2.998 x 10 to the 8 m/s. express this an (a) ft/s miles per hr (b) km/hr.

3. mercury freezes at -40 degrees C. what is the temperature in (a) fahrenheit scale? (b) kelvin scale.

4. in a certain experiment the circumference and radius of a disc were measured to be 21.95 cm and 3.51 cm, respectively. what is the computed value of pi? solve for the percent error.

5. express the angular speed of minute hand of an electric clock in (a) rev/sec (b) rad/sec (c) deg/sec.

Answer 1

1.
Area = 2500 * 1750 = 4375000 sq. ft

1 meter = 3.28 feet
Squaring both sides we have
1 sq. meter = 10.7584 sq. feet
So 1 sq. feet = 1/10.7584 sq. m
So, the area of the field = 406658.98 sq. meters

One hector = 10000 sq. m
So, 1 sq. m = 1/10000 hectors
So, the area of the field = 406658.98/10000 = 40.665 hectors

2.

2.998*10^8 m/s = 2.998*10^8*3.28 = 9.8334 * 10^8 ft/s

1 km = 1000m and 1 hr = 3600 sec
So,
2.998*10^8 m/s = 2.998*10^8*3600/1000 = 1.079 * 10^9 km/hr

3.

Temperature in Fahrenheit = Temperature in celcius * 9/5 + 32
So, in this case
Temperature in Fahrenheit = (-40 * 9/5) + 32
= -72 + 32 = -40

Temperature in Kelvin = Temperate in celcius + 273 = -40+273 = 233 K

4.
calculated pi =Circumference/Diameter= 21.95/(2*3.51) = 21.95/7.02 = 3.1468
The original pi = 3.1416
Percent error = (3.1468-3.1416)/3.1416 = 0.00165/1 = 0.1%

5.
The minute hand covers 1 revolution in 1 hour.

Angular speed = 1rev/hour

1 hour = 3600 sec
So angular speed = 1/3600 rev/sec = 0.000277 rev/sec

1 rev = 2π radians = 2*3.1416 radians = 6.2832 radians
So, speed = 1/3600 * 6.2832 = 0.001745 rad/sec

1 rev = 360 degrees
So speed = 1/3600 * 360 = 1/10 = 0.1 degree/sec

Answer 2

College? Really?

1. Assuming you mean length = 2500 feet, you get 4,375,000 sf
...4375000 sf / 107600 hectare/sf = 40.7 hectares

2. 2.998E8 m/s * 3.28 ft/m = 9.833E8 ft/s
....2.998E8 m/s * 3600 s/hr / 1609 m/mile = 6.708E8 mph
....2.998E8 m/s * 3600 s/hr / 1000 m/km = 1.079E9 kph

3. -40 degC = 9/5*-40 +32 = -40 deg F
...-40 degC = -40 +273 = 233 degK

4. Pi = C/2R = 21.95/(2*3.51) = 3.127 (t 4 sig figs)
...% error = (3.142 - 3.127)/3.142 = 4.774%

5. 1 rev/hr * hr/3600 sec = 2.8E-4 rev/sec
...2Pi rad/hr * hr/3600 = 1.74E-3 rad/sec
...360 deg/hr * hr/3600 = 0.1 deg/sec

Answer 3

1a..area of rectangular lot=2500x1750 ft^2
=4375000ft^2
b). 4375000/3.28^2=4375000/10.7584=406658m^2
c).406658/10000=40.6658 hectares
2a).speed of light=2.998x10^8x3.28=9.83x10^8ft/s
b).speed of light=2.998x10^8x3600/1000km/h=107.928x10^7km/h
3).a)on fahren heit scale =-40deg F
b) on kelvin scale=-40+273=233deg K.
4.r=3.51cm, c=21.95
pi=c/2r=21.95/7.02=3.063
5).a).angular speed= 1/60x60=2.77x10^-4 rev/s
b)angular speed=2pi/60x60=0.001745rad/s
c).angular speed=360/60x60=0.1deg/s

Answer 4

This looks like grade 4 physics problem