Questions, answers and multiple answers

[chawki]

Homework Statement

a) How many micrograms are equal to one kilogram?
b) What is the power dissipation of a light bulb of the kind commonly used in households? (In
your answer, give the order of magnitude only; the exact value is not required.)
c) By what factor will the kinetic energy of an object increase when its velocity increases by
50 %?
d) During its flight through air, a golf ball is affected by the following forces (select the
correct alternative and render the capital letter denoting it on your answer sheet):
A) gravity only
B) gravity and impact force
C) gravity, impact force and air resistance
D) gravity and air resistance
E) impact force and air resistance
e) Estimate the total consumption of fuel of all passenger cars in the US during one year.
f) A tape measure of steel has been manufactured and calibrated at a temperature of 20 °C.
When a measurement is performed using this tape measure at a temperature of 29 °C, the
results are (select the correct alternative and render the capital letter denoting it on your
answer sheet)
A) too great
B) too small
C) equally accurate as the measurement results at 20 °C.

Homework Equations

The Attempt at a Solution

a) 10⁹ micrograms.
b) P=V*I
c) ehhh 1/2*m*V² ?
d) D
e)
f) C

 

[rock.freak667]

a) correct
b) I think you just need to quote the wattage of the usual lightbulb.
c) You know that KE = 0.5mv², so what happens when 'v' is replaced by (1.5v)?
d) correct
e)Without looking that up, I am not sure how you're supposed to estimate that. Are you given some values to work with or something?
f) If you heat something up, what usually happens to it? (does it stay at the same length?)

 

[s200960170]

A stone is thrown vertically up from the edge of the top of a 100-m high building. It reaches the ground (at the bottom of the building) after 10.0 s. What is the initial speed of the stone?

A) 39.0 m/s
B) 29.0 m/s
C) 49.0 m/s
D) 59.0 m/s
E) 69.0 m/s

[PLEASE HELP]

 

[rock.freak667]

s200960170, you should start a new thread and follow the template outlined instead of posting your problem in another user's thread.

 

[s200960170]

sorry, I'm new here, i just registered my account, so I'm still getting used to this place, i never really used Forums before.
thank you for the information.
anyways, i would be really great full if you could help me with that above problem.

 

[chawki]

a) correct
b) I think you just need to quote the wattage of the usual lightbulb.
c) You know that KE = 0.5mv², so what happens when 'v' is replaced by (1.5v)?
d) correct
e)Without looking that up, I am not sure how you're supposed to estimate that. Are you given some values to work with or something?
f) If you heat something up, what usually happens to it? (does it stay at the same length?)

b) 60 watt (for example)?
c) 9/8 ?
e) no they did give nothing..that's why i was wondering what kind of question is this
f) it would extand a little bit regarding just 9C, but regarding the choices they gave..i still think the answer is C.

 

[rock.freak667]

b) 60 watt (for example)?
c) 9/8 ?
e) no they did give nothing..that's why i was wondering what kind of question is this
f) it would extand a little bit regarding just 9C, but regarding the choices they gave..i still think the answer is C.

c) try to get it as something* (0.5mv²)

e) I am not sure as well

f) Yeah, that is correct, since 'too great' or 'too small' implies a significant increase.

 

[chawki]

c) 9/4 *1/2*m*V^2
so it's 9/4 ?

 

[rock.freak667]

Yep.