Question

# Question 1 (1 point) Which is not necessary in order to do work on an object...

Question 1 (1 point)

Which is not necessary in order to do work on an object (use the scientific definition of work)?

Question 1 options:

 There must be a change in momentum. A net force must be applied to the object. The object must undergo a displacement. A component of the force must be in the direction of motion.

Question 2 (1 point)

The change in gravitational potential energy for a 1.9 kg box lifted 2.2 m is:

Question 2 options:

 41 N 4.1 N 90 N 0.43 N

Question 3 (1 point)

The change in kinetic energy in a 55.0 kg person who accelerates from a speed of 1.20 m/s to 6.50 m/s is:

Question 3 options:

 1.12 x 103 N 1.16 x 103 N 772 N 146 N

Question 4 (1 point)

A roller coaster’s first hill has a height of 32 m. At the bottom of the first hill, the coaster’s height is 16 m. Which of the following is true at this point?

Question 4 options:

 The coaster’s total energy is halved. The coaster has more kinetic energy than gravitational energy. The coaster has more gravitational energy than kinetic energy. The coaster’s energy is equally divided between gravitational and kinetic energy.

Question 5 (1 point)

An object drops from a height of 5.20 m. Its speed the instant before it hits the ground is:

Question 5 options:

 Not enough information given. 102 m/s 10.1 m/s 51.0 m/s

Question 6 (1 point)

An object is thrown upward with a speed of 7.6 m/s. Its maximum height will be:

Question 6 options:

 Not enough information given. 2.9 m 0.39 m 12 m

Question 7 (1 point)

When a dropped ball bounces on the floor, it usually does not regain its original height. This happens because:

Question 7 options:

 Conservation of energy is violated. An external force acts on the system. Energy is stored in the floor. Some energy is dissipated to the surroundings.

Question 8 (1 point)

Which of the following units is used for impulse?

Question 8 options:

 kg.m2/s2 N.s N/s kg.m/s2

Question 9 (1 point)

Determine the change in velocity on a 21.0 kg rock that experiences a 73.0 N change in force in 2.40 s:

Question 9 options:

 8.34 m/s 175 m/s 3.48 m/s 639 m/s

Question 10 (1 point)

During an inelastic collision with no external forces acting on the system:

Question 10 options:

 Only momentum is conserved. Only energy is conserved. Momentum and energy are conserved. Neither momentum nor energy is conserved.

Question 11 (1 point)

A ball rolls down a frictionless ramp. Momentum is not conserved because:

Question 11 options:

 Gravity is an external force acting on the ball. The interaction is inelastic. Elastic energy is stored in the ball. None of these options is correct.

Question 12 (1 point)

When solving conservation of energy problems in two dimensions:

Question 12 options:

 If solving algebraically, all velocities must be resolved into horizontal and vertical components. Horizontal and vertical energy are conserved independently. Energy vectors can be used to determine total initial and total final momentum. All of the options are incorrect.

Question 13 (1 point)

During an elastic collision of two objects with no external forces acting on the system:

Question 13 options:

 Only conservation of energy can be used to solve the problem. Only one unknown variable can be determined. Momentum and energy formulas can be combined to solve for two unknown variables. The initial given velocity of the second mass must be zero to solve for the final velocities of the two objects.

Question 14 (1 point)

During an elastic collision with no external forces acting on the system, a 1.00 kg ball travelling at 3.0 m/s collides with a stationary 0.50 kg ball. The final velocity of the 0.50 kg ball is:

Question 14 options:

 1.0 m/s [backward] 1.0 m/s [forward] 4.0 m/s [forward] 4.0 m/s [backward]

Question 15 (1 point)

If the spring constant of an elastic band is 2000 N/m, determine the amount of elastic potential energy it stores when stretched 2.5 c

Question 15 options:

 25 J 0.62 J 6.2 x 102 J 6.2 x 103 J

Question 16 (1 point)

The spring constant of an elastic band that requires 51 N to stretch it 3.2 cm is:

Question 16 options:

 16 N/m 1.6 x 103 N/m 1.6 x 102 N/m 1.6 x 10-3 N/m

Question 17 (1 point)

The collision of a speeding bullet and a block of wood is:

Question 17 options:

 Elastic because momentum is conserved. Inelastic because energy is not conserved. Elastic because energy is conserved. Not enough information is given.

Question 18 (1 point)

As it passes its rest position, a pendulum:

Question 18 options:

 Has no gravitational potential energy Has no kinetic energy Has a combination of gravitational potential and kinetic energy Is travelling at half its maximum speed

Question 19 (1 point)

A vertically oscillating spring:

Question 19 options:

 Will transfer energy between kinetic, gravitational potential, and elastic potential energy. Will transfer energy between kinetic, gravitational potential, and elastic potential energy. Will transfer energy between gravitational potential and elastic potential energy. Will transfer energy between kinetic and elastic potential energy.

Question 20 (1 point)

In simple harmonic motion, which of the following quantities can be modeled using trigonometric waves:

Question 20 options:

 Position Velocity Acceleration All of these options.

Work is defined as the measure of energy transfer. Hence given by work= Force *displacement.

So for a work to be done. Force has to be applied in the direction of the displacement.

So from the obtained relationship we concluded that the option - 4 is the correct answer as it is necessary to apply a force in the direction of the displacement.

As it is not mentioned that how many questions has to be attempted. Therefore I have done the first question as per instructions given to us. Kindly consider it please as this is our protocol if many questions are posted without mentioning that how many of them have to be attempted.

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