Mechanics | Relativity Answers

A 1000 kg Civic is travelling at 30 m/s and accelerates to 40 m/s in 10 seconds.
a. What is the change in momentum?
b. What is the impulse?
c. What is the net force that causes the change?

A 1000 kg Civic is travelling at 30 m/s and accelerates to 40 m/s in 10 seconds.
a. What is the momentum of the car before accelerating?
b. What is the momentum of the car after accelerating for 10 seconds?

Three particles are situated in 3-D space. The position of each particle is represented by the following vectors:
• A 5-kg particle at r1 = 4i + 3j + 5k
• A 3-kg particle at r2 = –3i + 5j + 3k
• A 6-kg particle at r3 = 5i – 6k
a. How far is each particle from the center of mass.

A 1200-kg station wagon is moving along a straight highway at 12.0 m/s. Another car, with mass 1800-kg and speed 20.0 m/s, has its center of mass 40.0 m ahead at the center of mass of the station wagon. Find the position of the center of mass of the system consisting two automobiles.

A 4-kg mass is at the origin and a 2-kg mass is at x=6 cm. Find the center of mass (x).

The 15-kg ball is connected with a spring as shown. Initially, the spring is compressed by 0.2m. the spring is stretched to 0.8 m. Determine the total work done to the ball during this process. the slope is smooth.

A thermal tap used in certain apparatus consists of a silica rod which fits tightly
inside an Aluminium tube whose internal diameter is 8 mm at 0℃ . When the
temperature is raised, the fit is no longer exact. Calculate what change in temperature
is necessary to produce a channel whose cross-section is equal to that of a tube of
1 mm internal diameter

. A flywheel used for storing energy consists of a uniform disk of mass 1.5x105
kg and radius 2.2 m that
rotates at 3000 rev/min about its center of mass Find its kinetic energy.

5. A soapbox derby race car starts at rest and moves 300 m down a track in 22.4 s. Calculate its acceleration (assumed constant) and its speed at the end of the track.

6. A car traveling at 35 mi/hr is stopped in a distance of 2.5 ft when it hits a tree. (a) Calculate the average deceleration of the car in m/s2. (b) Calculate the time needed to stop the car (assuming constant deceleration).

7. An automobile and a truck start from rest at the same instant, with the automobile initially at some distance behind the truck. The truck has a constant acceleration of 2 m/s2 and the automobile an acceleration of 3 m/s2. The automobile overtakes the truck after the truck has moved 75 m.
a) How long does it take the automobile to overtake the truck?
b) How far was the car behind the truck initially?
c) What is the velocity of each when they are abreast?