1. Nov 8, 2009

### wisehemlock

I have a this big assignment to get in, in not a big portion of my grade but I'll still get 2 days detention if I don't get it in, and I have to go to an important meeting tomorrow. This teacher is noted as being one of the worst at my school, she's totally incompetent, and no one likes her teaching methodes. To put it simply I LOVE Science and usually have a 96% or higher, this is the ONLY semester I have NOT...tell me there isn't a connection..! anyway here are the questions I CAN'T answer, since I have to have it in by midnight can someone PLEASE help me, I'm losing my mind!!!!!

(1.) Calculate the Mass.
PE = 1250J
Height = 6m
velocity = 2m/s

208.3kg
21.3kg
73500kg
or
21.3 g
______________________________________…

(2.) KE = 3000J
velocity = 8 m/s

96000 kg
187.5 kg
46.9kg
93.8kg
______________________________________…

(3.) Calculate the kinetic energy if an object that has a mass of 6kg is moving 3m/s2.

9J
18J
27J
27kJ
________________________________________…

(4.) Using the f=ma and w=fd formulas, calculate work if:

mass = 20kg

acceleration = 3m/s2

distance = 40m

1.5 J
2400N
2400J
240 J
________________________________________…

(5.) _________ describes potential energy.

stored energy
m/s2
mass times acceleration due to gravity
energy in motion
________________________________________…
(6.) How much work was done during the 1000m of the race?

Given Information:

During a bicycle race, a cyclist who had a mass of 50kg used a bike with a mass of 20kg. As he began the race, he was able to displace 100m the first 10sec of the race. As the race continued, his velocity increased to 25m/s at exactly 20sec of the race. He was able to maintain this acceleration for a total of 1000m.
1050kJ
70000J
75000J
1500J
1500N
105000J
________________________________________…
(7.) What is the mass of a golfball that has a momentum of 1 kg*m/s and is moving 25m/s?
0.04kg
100 kg
25 kg
0.04 kg*m/s
______________________________________…
(8.) ______________ describes kinetic energy.

energy in motion
stored energy
mass x acceleration due to gravity x height
Newton
________________________________________…
(9.) What unit describes work?
m/s2
N-m/s
J
kg *m2/s
________________________________________…
(10.) What is the total energy of a system that has 4000 J of potential energy and 1000 J of kinetic energy?
3000J
4 kJ
4000000 J
5000J
________________________________________…
(11.) Calculate power if it takes 60seconds to complete 30J of work.
2 W
0.5 W
1800 W
0.5 J
________________________________________…
(12.) Another way to describe a Newton is
kg*m*s
kg*m/s
m/s2
kg*m/s2
________________________________________…
(13.) Calculate distance if

work = 300J

and force = 3N
100m
10m
900m
10J
________________________________________…
(14.) What is the potential energy of a 0.5kg grapefruit just before it is dropped off a building rooftop that is 150m in height?
75 J
11250J
735 J
367.5 J
________________________________________…
(15.) What unit describes force?
Newton
joule
N-m
N-m2
________________________________________…
(16.) Calculate power if a it took a force of 30N to push a car a distance of 20m. The time it took to move the car 20 m was 0.5min.
20W
120 W
1200 W
1W
________________________________________…
(17.) Given Information:

During a bicycle race, a cyclist who had a mass of 50kg used a bike with a mass of 20kg. As he began the race, he was able to displace 100m the first 10sec of the race. As the race continued, his velocity increased to 25m/s at exactly 20sec of the race. He was able to maintain this acceleration for a total of 1000m.

If the cyclist hit a car at exactly 20secof the race, what force would he exert on the car?
105N
1250N
700N
75N
70kg
________________________________________…
(18.) What is the height of a tree if a 0.1kg apple has 20J of potential energy just before it falls to the ground?
20.4m
200m
40.8m
2.0m
________________________________________…
(19.) How long does it take to perform 100J of work with a power rating of 20W?
5 W
2000 W
5s
0.5 s
________________________________________…
(20.)What is the mass of an object that has 450J of kinetic energy and is moving at 30m/s?
15kg
1kg
30kg
0.5 kg
______________________________________…
(21.) Use the given information to calculate velocity:

mass = 60kg

PE = 3000 J

KE = 4000J
11.5m/s
89.4m/s
10m/s
133.3 m/s
______________________________________…
(22.) The final unit when calculating kinetic energy is _______.
Newton
kW
Joules
watt
________________________________________…
(23.) USe the given information to calculate potential energy:

mass = 50kg

velocity = 3m/s

height = 4m
1960J
5880J
600J
225J
________________________________________…
(24.) Calculate work if :

f= 30N and distance = 3000m
90000J
100J
9000J
90000N
______________________________________…
(25.) Calculate time if:

force = 25N

distance = 1000cm

power rating = 5W
5000s
500s
5 min
50s

Sorry There's so many, This isn't all of them F.Y.I. so I wasn't just like "hey man do this all for me." There's 57 questions, these are just the one's that I can't do. Please help me out! I have a spliting headache and I am EXTREMELY stressed out. Thank you!!!!!!
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Nov 8, 2009

### dotman

I'm sorry, but to be blunt, I don't see how you can't answer questions like the one's I quote below, or rather be completely stuck on them, if you maintain a 96% in the sciences.

I hope your headache feels better, but you're going to have to show some attempt at the problems before people will help you here.

3. Nov 8, 2009

Staff Emeritus