An Olympic track runner starts from rest and has an acceleration of 2.1 m/s2 for 3.5 s, then has zero acceleration for the remainder of the race. Find the runner's speed at the following times. (a) at time t = 1.3 s
m/s
(b) the end of the race
m/s

a) = 2.73 m/s

b) 7.35 m/s

Explanation:

runner starts from rest, initial velocity  u = 0 m/s

acceleration a = 2.1 m/s^2

time = 3.5 s

after the 3.5 s, his acceleration = 0

a) the time t = 1.3 s falls within the time frame where he was accelerating.

using the equation

v = 0 + (2.1 x 1.3)

v = 2.73 m/s

b) the end of the race fall outside the time frame in which the runner is accelerating.

This means that his speed at the end of the race will be equal to his speed at 3.5 s

we use the formula as before

v = 0 + (2.1 x 3.5)

v = 7.35 m/s

emily ruth's annual premium is $1058.50

step-by-step explanation:

emily ruth is a female of 27 years age purchasing 20 year endowment insurance with face value $25000.

from the given table,

for females, the age of a male 3 years younger should be used.

so, we have to check for 24 year male for 20 year endowment.

it is 42.34 for every $1000 face value.

for a face value of $25000,

it is 25 * 42.34 = $1058.50

∴ emily ruth's annual premium is $1058.50

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