Recent content by jumptheair

Homework Statement An object is undergoing simple harmonic motion. The graph shows the position of the object as a function of time. What is the first time after t = 0 s when the speed reaches a maximum? http://www.learning.physics.dal.ca/dalphysicslib/Graphics/Gtype26/shm.47.jpeg...

Why would 1. and 2. be false? Or are they true? HELP!

Arr.. still wrong.. help is still needed

Homework Statement 1.Consider a train that pulls a wagon. By Newton's third law, the wagon pulls on the train with an equal opposite force, therefore the work done by the train must be zero. 2.Negative net work done on an object always reduces the object's kinetic energy. 3.Two...

Homework Statement Consider a spring with spring constant k = 8.42 N/m with an unstretched length of 0.250 m. How much work do you do on the spring in stretching it from a length of L1 = 0.450 m to a length of L2 = 0.559 m? Homework Equations F= kx W=(1/2) kx^2 The Attempt at a...

Oh right! I was thinking that normal force is in opposite direction to gravity, but it's the surface. Thanks!

1. Friction down, because it opposes motion? Is this correct? If so, what effect does the decreasing velocity have? 4. Common sense tells me friction would act upwards but my book says the frictional force is ALWAYS perpendicular to the normal force, so I am confused.

Ok. I am convinced that 1. is sliding up the ramp. If 4 is sliding downwards, would it be going down at increasing speed because w,x is greater in magnitude than fk so Fnet is positive (downwards) so that acceleration is also positive(downwards)?

Direction of frictional force! Help! Homework Statement What is the direction of the frictional force for each question? OR is there not enough info given to answer the question? 1) http://www.learning.physics.dal.ca/library/Graphics/Gtype10/block01-19.gif 2)...

For 1, as you see in the FBD, only fk is drawn. I don't know if ALL forces are drawn in but without a pushing force, the fk and gravity will bring it down right? I am not sure for which cases but i remember that friction doesn't ALWAYS oppose motion. I am confused. For 4, the fk is drawn so...

tension is only involved in 3. These are the given FBD: 1. http://www.learning.physics.dal.ca/library/Graphics/Gtype10/blockfbd1.gif 2. http://www.learning.physics.dal.ca/library/Graphics/Gtype10/blockfbd6.gif 3. http://www.learning.physics.dal.ca/library/Graphics/Gtype10/blockfbd2.gif 4...

Got it. Thanks!

Homework Statement A block is on a ramp. What is happening to the block for each of the following situations?: 1. fk(down the ramp) 2. fs(up the ramp) < w,x(down) 3. Tension(up) > fk(down) + w,x(down) 4. fk(up) < w,x(down)..FBD also looks like fk(up) magnitude is equal to fs(up) from 2...

Got it. Thanks alot!

Homework Statement You have been called to testify as an expert witness in a trial involving an automobile accident. The posted speed limit was 70 km/h . The driver of the car slammed on his brakes, locking the wheels, and left skid marks as the car skidded to a halt. You measure the length...