# Multiple Choice Question son Velocity and Tension

A particle moves according to the equation x = 10t2, where x is in meters and t is in seconds. Find the average velocity for the time interval from 2.0 second to 3.0 second.

50 m/s

100 m/s

250 m/s

200 m/s

A particle undergoes three consecutive displacements:

d1 = (10i + 30j + 12k), d2 = (23i - 14j -22k), and d3 = (-15i + 20j).

Find the magnitude of the resultant displacement.

61 m

51 m

41 m

21 m

A rescue plane drops a package of emergency rations to a stranded party of explorers, as shown in the figure below. If the plane is traveling horizontally at speed of 40 m/s and is 100 m above the ground, where does the package strike the ground relative to the point at which it was released?

19 m

100 m

181 m

276 m

A force F applied to an object of mass m1 produces an acceleration of 3 m/s2. The same force applied to a second object of mass m2 produces an acceleration of 1 m/s2. What is the value of the ratio of m1/m2?

1/3

1

1/4

1/5

A 0.400 kg object is swung in a vertical circular path on a string 0.500 m long. If its speed is 4.00 m/s at the top of the circle, what is the tension in the string there?

4.44 N

6.41 N

8.88 N

12.23 N

The potential energy function for a system is given by U(x) = -x3 +2x2+3x. For what value(s) is the force equal to zero?

-0.535

1.87

3.74

Both A and B

A 2.0 kg object is attached to a horizontal spring. The spring is initially stretched 0.150 m, and the object is released from there. It proceeds to move without friction. The next time the speed of the object is zero is 0.3 seconds later. What is the maximum speed of the object?

1.57 m/s

3.14 m/s

10.47 rad/s

20.94 rad/s

A gasoline engine has a compression ratio of 6.0 and uses a gas for which cp/cv = 1.40. What is the efficiency of the engine if it operates in an idealized Otto cycle?

3.62 %

36.2 %

5.12 %

51.2 %

The femur (upper leg bone) is the longest and strongest bone in the body. Taking a typical femur to be approximately circular with a radius of 2.0 cm, how much force would be required to extend the bone by 0.010 %? Y= 1.5 x 1010 N/m2.

1.9 x 102 N

1.9 x 103 N

1.9 x 104 N

1.9 x 105 N

A uniform thin solid door has height 2.20 m, width 0.870 m, and mass 23.0 kg. Find its moment of inertia for rotation on its hinges.

5.8 kg-m2

58.0 kg-m2

17.2 kg-m2

172.0 kg-m2

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#### Solution Preview

A particle moves according to the equation x = 10t2, where x is in meters and t is in seconds. Find the average velocity for the time interval from 2.0 second to 3.0 second.

x(t)=10t^2

(x(3)-x(2))/(3-2)=(90-40)=50 (m/s)

A particle undergoes three consecutive displacements:

d1 = (10i + 30j + 12k), d2 = (23i - 14j -22k), and d3 = (-15i + 20j).

Find the magnitude of the resultant displacement.

d1+d2+d3=(18i+36j-10k)

displacement = sqrt(18*18+36*36+10*10)=41.47 (m)

A rescue plane drops a package of emergency rations to a stranded party of explorers, as shown in the figure below. If the plane is traveling horizontally at speed ...

#### Solution Summary

431 and explained calculations to show how to find average velocity, magnitude of displacement, tension in a string and other objectives in this assorted problem set.