Physics - March 2007

An 85-N box of oranges is being pushed across a horizontal floor. As it moves, it is slowing at a constant rate of 0.90 m/s each second. The push force has a horizontal component of 20 N and a vertical component of 25 N downward. Calculate the coefficient of kinetic friction between the box and floor.

2007-03-22 23:14:21 · 2 answers · asked by biscuits 2

If the past is nothingness and nothingness is our future, isn't time just a false perception? when in reality our Universe is only a constant present?

2007-03-22 22:58:30 · 7 answers · asked by Anonymous

1. Why is the cooling unit placed at the top of the refrigerator?
a)Cold air falls and warm air is displaced upwards.
b)Cold air is a bad conductor so heat is not conducted into the fridge.
c) Cold air is a good conductor so heat is conducted out of the fridge.
d) cold air stops at the top and so prevents convection.
2. Which substance is a liquid @ room temperature of 25*C?
a) Melting point = -218 boiling point = -193
b) Melting point = -39 boiling point = 357
c) melting point = 44 boiling point = 280
d) melting point = 119 boiling point = 444
3) a long bar copper is heated evenly along its length, what happens to the bar?
a) it becomes lighter
b) it becomes longer
c) it becomes shorter
d) it bends at the end.
4) four blocks, made of different materials, are each given the same quantity if internal (heat) energy. Which block has the greater thermal capacity?
a) Temperature rise = 2*C
b) Temperature rise = 4*C
c) Temperature rise = 6*C
d) Temperature rise = 8*C

2007-03-22 22:40:23 · 3 answers · asked by Jaimee Ariane 3

A 8 kg of ice, released from rest at the top of a 1.50 m long frictionless ramp, slides downhill, reaching speed of 2.50 m/s at the bottom. what is the angle between the ramp and the horizontal?

2007-03-22 22:32:58 · 3 answers · asked by biscuits 2

a runaway truck with failed brakes is moving downgrade at 102 km/h just before the driver steers the truck up a frictionless emergency escape ramp with an inclination of = 10°. The truck's mass is 1.2 x 104 kg. (a) What minimum length L must the ramp have if the truck is to stop (momentarily) along it? (Assume the truck is a particle). What is the minimum length L if (b) the truck's mass is decreased by 21% and (c) its speed is decreased by 34%?

thanks very much

2007-03-22 22:28:17 · 4 answers · asked by Wilson J 4

2007-03-22 21:45:53 · 6 answers · asked by lance s 1

Driving a car raises temperature of the tyres.
This causes the pressure of the air in the tyres to increase.
Why is this?
A Air molecules break up to form separate atoms.
B Air molecules expand with the rise in temperature.
C The force between the air molecules increases.
D The speed of the air molecules increases.

To mark a temperature scale on a thermometer, fixed points are needed.
Which is a fixed point?
A The bottom end of the thermometer
B The top end of the thermometer
C The temperature of pure melting ice
D The temperature of pure warm water

4a) State two differences between evaporation of water and boiling of water.
b) The specific latent heat of vaporization of water is 2250 kJ/kg.
Explain why this energy is needed to boil water and why the temperature of the water does not change during the boiling.

2007-03-22 21:40:48 · 4 answers · asked by Jaimee Ariane 3

if we could travel that fast wouldnt the smallest of objects (i.e space debry) we colided with destroy the vessel we were in ?

2007-03-22 21:30:13 · 13 answers · asked by Red5 5

are atoms real

2007-03-22 21:25:45 · 9 answers · asked by tim w 1

2007-03-22 21:20:29 · 7 answers · asked by Anonymous

2007-03-22 19:37:00 · 3 answers · asked by S.N.Rao 2

2007-03-22 19:35:30 · 6 answers · asked by princess 1

is that bonding more powerful than H2 BONDING

2007-03-22 19:32:13 · 3 answers · asked by S.N.Rao 2

1.1kg mass hangs from a spring with a force constant 400N/m. the mass is pulled down 13 cm from the equilibrium position and released. at the end of 5 complete cycles of vibration the mass reaches only 10cm from the equilibrium position.
a) how much mechanical energy is lost during these 5 cycles
b) what % of the mechanical energy is lost during the 5 cycles

2007-03-22 19:29:31 · 3 answers · asked by pookie 1

Find the centripetal accelerations at each of the following points due to the rotation of Earth about its axis.
(a) a point on the Equator of Earth
The average distance separating Earth and the Moon (center to center) is 384 000 km. Use the data in Table 7.3 to find the net gravitational force exerted by Earth and the Moon on a 3.00 104 kg spaceship located halfway between them.
N
Objects with masses of 210 kg and a 510 kg are separated by 0.320 m.
(a) Find the net gravitational force exerted by these objects on a 31.0 kg object placed midway between them.

Your answer differs from the correct answer by 10% to 100%. N
(b) At what position (other than infinitely remote ones) can the 31.0 kg object be placed so as to experience a net force of zero?

Your answer differs from the correct answer by orders of magnitude. m from the 510 kg mass

Also tell mne how to freaking set these up. THANKS

2007-03-22 19:04:49 · 1 answers · asked by happygolucky 6

2007-03-22 18:54:07 · 4 answers · asked by princess 1

a 2000kg truck has a 100kw engine and is travelling 120 km per hour.
find ;
a.time it would take to travel 2km
b.how much work is done by the engine during this time
c. what the force being exerted on the truck during this time

2007-03-22 18:50:43 · 2 answers · asked by harry s 1

ok . im confused

carbon atoms have a less mass than silicon. Diamonds are made of carbon. But diamons are more dense than silicon. Whys that?

2007-03-22 18:36:20 · 6 answers · asked by ♥ hey! 2

2007-03-22 18:23:49 · 2 answers · asked by stayin alive 2

2007-03-22 18:22:18 · 2 answers · asked by Rimi M 1

2007-03-22 18:10:04 · 3 answers · asked by iSmile 2

2007-03-22 17:52:30 · 3 answers · asked by stayin alive 2

given;
a car with
m=1500 kg
p= 75watts
v= 120 km per hour

find
a.time it would take the car to reach 1km
b.force exerted in the car during this time
c.the work done by the engine during this time

2007-03-22 17:48:31 · 1 answers · asked by Anonymous

2007-03-22 17:37:37 · 12 answers · asked by Anonymous

The question is What is the current in the circuit
How much thermal energy is produced in 10 minutes
Thanks everyone who helps me with this problem in advance im really grateful for your help God Bless You

2007-03-22 17:25:45 · 10 answers · asked by josh h 3

IS Pluto really a planet or not?

2007-03-22 17:24:34 · 4 answers · asked by ave angelo b 1

2007-03-22 17:19:06 · 3 answers · asked by frontstreetboy2004 3

A second cylinder has a radius of 2.75" and a length of 1" has what volume?

How much greater in volume is cyl.2 than cyl.1 ?

2007-03-22 17:11:23 · 7 answers · asked by Norrie 7

Please i have this assignment due tommorrow and i need all the help i can get thanks in advance

2007-03-22 17:00:52 · 4 answers · asked by josh h 3

what is the answer and how do you get it?

2007-03-22 16:59:10 · 7 answers · asked by stayin alive 2