Biology Forums - Study Force

An object is thrown vertically and has an upward velocity of 18 m/s when it reaches one fourth of its maximum height above its launch point. What is the initial (launch) speed of the object?
 a. 35 m/s
  b. 25 m/s
  c. 30 m/s
  d. 21 m/s
  e. 17 m/s

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[Ques. 2] A ball is thrown vertically upward with an initial speed of 20 m/s. Two seconds later, a stone is thrown vertically (from the same initial height as the ball) with an initial speed of 24 m/s. At what height above the release point will the ball and stone pass each other?
 a. 17 m
  b. 21 m
  c. 18 m
  d. 27 m
  e. 31 m

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[Ques. 3] Two singly ionized isotopes, X and Y, of the same element move with the same speed perpendicular to a uniform magnetic field. Isotope X follows a path of radius 3.37 cm while isotope Y moves along a path 3.58 cm in radius. What is the ratio of the two isotope masses, ?
   
  a.
  0.941
   
  b.
  1.06
   
  c.
  0.886
   
  d.
  1.13
   
  e.
  Not enough information is given.

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[Ques. 4] A rocket, initially at rest, is fired vertically with an upward acceleration of 10 m/s2 . At an altitude of 0.50 km, the engine of the rocket cuts off. What is the maximum altitude it achieves?
 a. 1.9 km
  b. 1.3 km
  c. 1.6 km
  d. 1.0 km
  e. 2.1 km

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[Ques. 5] A particle starts from rest at xi = 0 and moves for 10 s with an acceleration of +2.0 cm/s2 . For the next 20 s, the acceleration of the particle is 1.0 cm/s2 . What is the position of the particle at the end of this motion?
 a. zero
  b. +3.0 m
  c. 1.0 m
  d. +2.0 m
  e. 3.0 m

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[Ques. 6] An electron moves through a region of crossed electric and magnetic fields. The electric field E = 2 300 V/m and is directed straight down. The magnetic field B = 0.95 T and is directed to the left. For what velocity v of the electron into the paper will the electric force exactly cancel the magnetic force?
 
   
  a.
  2 400 m/s
   
  b.
  2 200 m/s
   
  c.
  3 500 m/s
   
  d.
  4 400 m/s
   
  e.
  3 800 m/s

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[Ques. 7] An electron, starting from rest and moving with a constant acceleration, travels 2.0 cm in 5.0 ms. What is the magnitude of this acceleration?
 a. 2.5 km/s2
  b. 0.80 km/s2
  c. 1.6 km/s2
  d. 1.3 km/s2
  e. 3.2 km/s2

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[Ques. 8]

A stationary positive charge +Q is located in a magnetic field B, which is directed toward the right as indicated. The direction of the magnetic force on Q is:
   

   
  a.
  toward the right.
   
  b.
  up.
   
  c.
  down.
   
  d.
  There is no magnetic force.

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[Ques. 9] An object moving on the x axis with a constant acceleration increases its x coordinate by 80 m in a time of 5.0 s and has a velocity of +20 m/s at the end of this time. Determine the acceleration of the object during this motion.
 a. 1.6 m/s2
  b. +6.4 m/s2
  c. +1.6 m/s2
  d. 2.0 m/s2
  e. 6.4 m/s2

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[Ques. 10] A circular loop is suspended in a uniform magnetic field as shown in the figure.
 
 
  If the loop area increases, what affect does this have on the induced current?
   
  a.
  The induced current is clockwise.
   
  b.
  The induced current is counterclockwise.
   
  c.
  There is no induced current.
   
  d.
  We would need to know the magnitude of the magnetic field.

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