Whenever you are faced with adding vectors acting in a straight line (i.e. some directed left and some right, or some acting up and others down) you can use a very simple algebraic technique:
Method: Addition/Subtraction of Vectors in a Straight Line
Choose a positive direction. As an example, for
situations involving displacements in the directions west and east, youmight choose west as your positive direction. In that case,
displacements east are negative.
Next simply add (or subtract) the
magnitude of the vectors using the appropriate signs.
As a final step the direction of the resultant should be included in
words (positive answers are in the positive direction, while negativeresultants are in the negative direction).
Let us consider a few examples.
A tennis ball is rolled towards a wall which is 10 m away from the ball. If after striking the wall the ball rolls a further 2,5 m along the ground away from the wall, calculate algebraically the ball's resultant displacement.
We know that the resultant displacement of the ball
(
) is equal to the sum of the ball's separate
displacements (
and
):
Since the motion of the ball is in a straight line (i.e. the ball
moves towards and away from the wall), we can use the method of algebraic additionjust explained.
Let's choose the
positive direction to be towards the wall. This means that the
negative direction is away from the wall.
With right positive:
Next we simply add the two displacements to give the resultant:
Finally, in this case
towards the wall is the positive direction , so:
= 7,5 m towards the wall.
Suppose that a tennis ball is thrown horizontally towards a wall at an initial velocity of
to the right. After striking the wall, the ball returns to the thrower at
. Determine the change in velocity of the ball.
A quick sketch will help us understand the problem.
Remember that velocity is a vector. The change in the velocity of the
ball is equal to the difference between the ball's initial and finalvelocities:
Since the ball moves along a straight line (i.e. left and right), we
can use the algebraic technique of vector subtraction just discussed.
Choose the
positive direction to be towards the wall. This means that the
negative direction is away from the wall.
Thus, the change in velocity of the ball is:
Remember that in this case
towards the wall means a positive velocity , so
away from the wall means a negative velocity :
away from the wall.
Questions & Answers
A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
