From: Subject: Energy, Work & Power (multiple choice test) Date: Wed, 29 Dec 2004 06:48:05 -0500 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_0105_01C4ED72.59B05700" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0105_01C4ED72.59B05700 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Location: http://prkw.com/pmcwep.html Energy, Work & Power I
Multiple Choice Online Test
Indicate the correct = answer by=20 clicking on the button next to the numbers 1, 2, 3 or 4. There = is only=20 one correct answer per question. After you have answered=20 all multiple choice questions compare your choices = with=20 the correct answers.

Energy, Work & Power

1.) An object moving in a straight line = with a=20 constant velocity has kinetic energy E and momentum p. If the = speed of=20 the object is doubled, the new value of kinetic energy and momentum = will be=20 =85=20
     
    Kinetic Energy
    Momentum
    1
    2 E
    2 p
    2
    2 E
    4 p
    3
    4 E
    p
    4
    4 E
    2 p
    k =3D 1/2mv2, doubling v = increases Ek by 4. p =3D mv, doubling v doubles the momentum. = Only option 4 offers 4 Ek and 2 p.")' type=3Dbutton = value=3DExplanation>
2.) A ball is projected vertically upwards and = then returns=20 to the ground. Ignore all frictional forces. Which one of the = following=20 statements about the kinetic energy and potential energy of the ball = is true?=20
    1 The kinetic energy is always equal to the potential = energy.
    2 The kinetic energy is always less than the potential = energy.
    3 The kinetic energy is always more than the potential = energy.
    4 The sum of the kinetic energy and potential energy is always = constant.
3.) An object is dropped from the top of a high = building and=20 falls freely to the ground. Which one of the graphs below best = represents its=20 potential energy (Ep) as a function of the distance fallen by the = object?=20
    3D"energy,

    1
    A
    2
    B
    3
    C
    4
    D
    p =3D mgh is a linear function = (straight line graph), which is only given in option 1. Or in other = words: the amount of potential energy decreases - on falling - by the = same amount for equal distances/heights. ")' type=3Dbutton = value=3DExplanation>
4.) A large and a small sphere are released at the = same time=20 from the same height above the ground. Which one of the following = quantities=20 associated with the spheres will be the same for both after 1 second, = if=20 frictional effects are ignored?
    1 speed
    2 momentum
    3 potential energy
    4 kinetic energy
5.) Which one of the following expressions has the = same=20 units as power?
    1 force x distance
    2 work x time
    3 force x acceleration
    4 force x = velocity
6.) A person lifts a heavy load to a vertical = height of 2,0=20 m in 3 seconds. If he/she had done this more slowly in 6 seconds, the = work on=20 the load would have been:
    1 twice as great
    2 four times as great
    3 the same
    4 half as great
7.) At what height above the ground must a mass of = 10 kg be=20 to have a potential energy equal in value to the kinetic energy = possessed by a=20 mass of 10 kg moving with a velocity of 20 m/s?
    1 10 m
    2 20 m
    3 50 m
    4 100 m
    k of a body of mass 10 kg with speed = 20 m/s =3D 1/2 mv2 =3D 1/2 =B710=B7(20=B720) =3D 5 =B7 400 = =3D 2000J. Ep =3D m=B7g=B7h =BB h =3D Ep/m=B7g =3D = 2000/100 =3D 20 m.")' type=3Dbutton value=3DExplanation>
8.) A girl runs up one flight of steps. Which one = of the=20 following factors does not affect the work done by the girl against = gravity?=20
    1 mass of the girl
    2 height of the steps
    3 speed of the girl
    4 acceleration due to gravity
    p =3D mgh, mass m referred to = in option 1, height h referred to in option 2 and force due to gravity = in option 4.")' type=3Dbutton value=3DExplanation>
9.) A girl weighing 400 N runs up the a flight of = stairs=20 (height 5 m) in a time of 4 seconds. Her rate of working against = gravity is=20 ...
    1 320 W
    2 400 W
    3 500 W
    4 2000 W
10.) A stone dropped from the top of a 80m high = building=20 strikes the ground at 40 m/s after falling for 4 seconds. The stone's=20 potential energy with respect to the ground is equal to its kinetic = energy =85=20
    1 at the moment of impact.
    2 2 seconds after the stone is released.
    3 after the stone has fallen 40 m.
    4 when the stone is moving at 20 = m/s.
    p=3D mgh =3Dm=B710=B780 =3D 800m at the top of the building. = When does it Ek equals this value? Ek=3D = Ep =3D 800m =3D 1/2mv2. Hence 1600 =3D = v2 or v =3D 40 m/s.")' type=3Dbutton value=3DExplanation>
Results
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