April 24, 2014

Homework Help: PHYSICS

Posted by Hayden on Friday, December 21, 2012 at 2:26am.

1. A sound with a frequency of 261.6 Hz travels through water at a speed of 1435 m/s. What is the wavelength of the wave?

a. 1.83 x 10 -1 m
b. 3.753 x 10 5 m
c. 5.486 m
d. You cannot tell from the given information

2. A 23.0 kg mass of is accelerated at + 4.50 m/s2. What is the force acting on the mass?

a. 1.95 x 10 -1 N
b. +104 N
c. + 5.11 N
d. 225.4 N

3. A 72.34 kg skater accelerates to a stop with a force of - 34 .4N. What is the skater’s acceleration?

a. – 2.49 x 10-3 m/s2
b. + 2.49 x 10-3 m/s2
c. – 4.75 x 10-1 m/s2
d. 2.10 m/s2

4. In the absence of friction, the net force required to keep a 6.00-kg object moving with a constant velocity of 2.000 m/s is __ N.

a. 0.333 N
b. 2. 3 N
c. 12 N
d. No force is required to keep the object in motion.

5. If the net force acting upon an object is 0 N, then the object MUST ____.

a. be moving
b. be accelerating
c. be at rest
d. be moving with a constant speed in the same direction
e. Either c or d.

6. A desk is stationary in the room. A person tries to pushes on the desk to try to start it into motion. The desk does not move at all. The desk remains at rest because ______.

a. there is a force of static friction opposing its motion
b. there is an unbalanced force on the desk
c. there is a force of gravity opposing its motion
d. there are small dust bugs on the desk's feet which push back on the desk to keep it at rest

7. Newton assumed light consisted of particles. Which of the following properties of particles of light explains why light does not slow down when it is reflected?

a. They travel at very high speeds
b. They make elastic collisions
c. Each colour of light has a different very small mass
d. They are small compared to the spaces between them
e. They are affected by gravitational forces

8. A 5.770 kg object slides to the right along a surface with a co-efficient of friction of 0.404. The normal force is + 56.55 N. What is the force of friction?

a. - 22.85 N
b. -2.331 N
c. + 326.3 N
d. + 751 N

9. An apple is thrown into the air and is moving upwards and toward the right towards its peak. Assuming no air friction, the ball experiences a force which is _______

a. Directed upwards and to the right.
b. Directed downward and to the right.
c. Directed downward only.
d. Directed upward only.

10. A car horn produces a 5000 Hz sound. You hear the sound as 4700 Hz. Therefore the car is ___________.

a. moving towards you.
b. moving away from you.
c. is not moving.
d. There is not enough information about the car to decide.

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