Itraveled 3.8 miles in 12 minutes. calculate my average velocity in miles per hour. 2) a sprinter increased his/her speed from 18 mph to 28 mph over 3.5 seconds. calculate his/her acceleration.

1) Average velocity: 19 mi/h

The average velocity is given by:

where

d is the displacement

t is the time taken

In this problem,

d = 3.8 mi is the displacement

is the time taken

Substituting,

Note that this is actually the average speed, not the average velocity, since there is no information about the direction of the motion.

2)

The acceleration is given by

where we have

v = 28 mph is the final velocity

u = 18 mph is the initial velocity

t = 3.5 s is the time taken

Conerting the time from seconds to hours,

So the acceleration is

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz

ok

explanation: