Peoples Physics Book Version-2

(Marvins-Underground-K-12) #1

http://www.ck12.org Chapter 9. Energy and Force Version 2


b. What is the change in velocity during the first 10 sec?
c. What is the acceleration at 4 sec?
d. What is the total work done on the cart by the force from 0−10 sec?
e. What is the displacement after 5 sec?


  1. Force is applied in the direction of motion to a 4.00 kg cart on a frictionless surface. The motion is along a
    straight line and whent= 0 ,v=0 andx=0. look at the following graph:


a. What is the acceleration of the cart when the displacement is 4 m?
b. What work was done on the cart betweenx=3 m andx=8 m?
c. What is the total work done on the cart between 0−10 m?
d. What is the speed of the cart atx=10 m?
e. What is the impulse given the cart by the force from 1−10 m?
f. What is the speed atx=8 m?
g. How much time elapsed from when the cart was atx=8 to when it got tox=10 m?


  1. You are to design an experiment to measure the average force an archer exerts on the bow as she pulls it back
    prior to releasing the arrow. The mass of the arrow is known. The only lab equipment you can use is a meter
    stick.


a. Give the procedure of the experiment and include a diagram with the quantities to be measured shown.
b. Give sample calculations using realistic numbers.
c. What is the single most important inherent error in the experiment?
d. Explain if this error would tend to make the force that it measured greater or lesser than the actual force
and why.


  1. Molly eats a 500 kcal( 2. 09 × 106 J)power bar before the big pole vault. The bar’s energy content comes from
    changing chemical bonds from a high to a low state and expelling gases. However, 25.0% of the bar’s energy
    is lost expelling gases and 60.0% is needed by the body for various biological functions.

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