Question

4) The distance needed to bring a truck to a stop varies as the square of its speed. If a truck travels at a speed of 55 mph it needs 79 feet to stop. What is the stopping distance of the truck travelling at 70 mph?

5) A principal of $7000 is invested in an account paying an annual rate of 5%. Find the amount in the account after 5 years if the account is compounded semiannually, quarterly, and monthly.

Answer 1

d = (70/55)^2 * 79 = 128 Ft.

Answer 2

5. P = Po(1+r)^n.

Sem1-annually:
Po = $7,000.
r = (5%/2)/100% = 0.025 = Semi-annual %
rate expressed as a decimal.
n = 2Comp./yr. * 5yrs. = 10 Compounding
periods.

P = 7000 * (1.025)^10 = $8960.59.

Quarterly:
r = (5%/4)/100% = 0.0125 = Quarterly % rate expressed as a decimal.
n = 4comp./yr. * 5yrs. = 20 Compounding
periods.
P = ?.

Monthly:
r = (5%/12)/100% = 0.0042 = Monthly % rate expressed as a decimal.
n = 12comp./yr. * 5yrs. = 60 Compounding
periods.
P = ?.