Biology Forums - Study Force

Rupel pushes a box 7.00 m by applying a 25.0-N horizontal force. What work does she do?
 a. 3.57 J
  b. 0.280 J
  c. 175 J
  d. 175.0 J
  e. 25.0 J

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[Ques. 2] The unit of work, joule, is dimensionally the same as:
 a. newton/second.
  b. newton/kilogram.
  c. newton-second.
  d. newton-meter.

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[Ques. 3] A suitcase is sitting on a horizontal conveyor belt, which is moving at speed v. The work done by the frictional force on the suitcase is
 a. positive.
 b. negative.
 c. zero.
 d. impossible to determine without knowing the mass of the suitcase.

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[Ques. 4] A box slides across a floor and comes to rest. The work done by the frictional force on the box is
 a. positive.
 b. negative.
 c. zero.
 d. impossible to determine without knowing the coefficient of friction.

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[Ques. 5] A miniature, spring-loaded, radio-controlled gun is mounted on an air puck. The gun's bullet has a mass of 6.00 g, and the gun and puck have a combined mass of 130 g. With the system initially at rest, the radio-controlled trigger releases the bullet, causing the puck and empty gun to move with a speed of 0.500 m/s. Of the total kinetic energy of the gun-puck-bullet system, what percentage is in the bullet?
 a. 4
  b. 98
  c. 96
  d. 23
  e. 100

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[Ques. 6] An unfueled 1000-kg experimental rocket sled at rest on level frictionless rails is loaded with 50 kg of propellant. It exhausts the propellant in a 20 s burn.. The rocket moves at 160 m/s after the burn. What average force is experienced by the rocket during the burn?
 a. 0.80  104 N b. 0.75  104 N
  c. 0.60  104 N d. 0.35  104 N

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[Ques. 7] An unfueled 1 000-kg experimental rocket sled on level frictionless rails is loaded with 50 kg of propellant. It exhausts the propellant in a 20-s burn.. If the rocket, initially at rest, moves at 160 m/s after the burn, what impulse is experienced by the rocket sled?
 a. 1.1  105 kgm/s b. 1.6  105 kgm/s
  c. 1.5  105 kgm/s d. 1.9  105 kgm/s

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[Ques. 8] A rocket of total mass M and with burnout mass 0.20M attains a speed of 3 400 m/s after starting from rest in deep space. What is the exhaust velocity of the rocket?
 a. 6.8E+2 m/s
  b. 2.1E+3 m/s
  c. 1.7E+4 m/s
  d. 2.2E+3 m/s
  e. 1.1E+3 m/s

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[Ques. 9] Neglecting gravity, doubling the exhaust velocity from a single stage rocket initially at rest changes the final kinetic energy of the burnout stage by what factor? Assume all other variables, such as the mass of the rocket and the mass of the fuel, do not change.
 a. It is the same.
  b. It doubles.
  c. It quadruples.
  d. It increases by a factor of 1.693.

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[Ques. 10] At liftoff, the engines of the Saturn V rocket consumed 12 500 kg/s of fuel and exhausted the combustion products at 2 700 m/s. What was the total upward force (thrust) provided by the engines?
 a. 3.38E+7 N
  b. 4.63E+6 N
  c. 2.16E+5 N
  d. 3.48E+7 N
  e. 3.28E+7 N

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So very smart