Question

List the following items in order of decreasing speed, from greatest to least: (i) A wind-up toy car that moves 0.15 m in 2.5 s. (ii) A soccer ball that rolls 2.3 m in 0.55 s. (iii) A bicycle that travels 0.60 m in 0.075 s. (iv) A cat that runs 8.0 m in 2.0 s. Knight, Randall D., (Professor Emeritus). College Physics (p. 28). Pearson Education. Kindle Edition.

Answer 1

Answer:

(iii) > (ii) > (iv) > (i)

Explanation:

Part (i):

$\textrm{Speed of the wind-up toy} = \dfrac{\textrm{distance traveled}}{\textrm{Time taken}}\\\Rightarrow v_1=\dfrac{0.15\ m}{2.5\ s}\\\Rightarrow v_1 = 0.06\ m/s$

Part (ii):

$\textrm{Speed of the soccer ball} = \dfrac{\textrm{distance traveled}}{\textrm{Time taken}}\\\Rightarrow v_2=\dfrac{2.3\ m}{0.55\ s}\\\Rightarrow v_2 = 4.18\ m/s$

Part (iii):

$\textrm{Speed of the bicycle} = \dfrac{\textrm{distance traveled}}{\textrm{Time taken}}\\\Rightarrow v_3=\dfrac{0.66\ m}{0.075\ s}\\\Rightarrow v_3 = 8.8\ m/s$

Part (iv):

$\textrm{Speed of the cat} = \dfrac{\textrm{distance traveled}}{\textrm{Time taken}}\\\Rightarrow v_4=\dfrac{8.0\ m}{2.0\ s}\\\Rightarrow v_4 = 4.0\ m/s$

From the above calculations, we have

$v_3>v_2>v_4>v_1$

So, the speed in the parts mentioned arranged in decreasing order as follow:

(iii) > (ii) > (iv) > (i)