Please help these two questions show working
thank you :)​

a) The acceleration between 20 and 40 seconds is equal to the slope in that range.

Remember that for aline that passes through the points (a, b) and (c, d) the slope is:

slope = (d - b)/(c - a)

In this case we can see the points:

(20s, 2m/s) and (40s, 4m/s)

Then the slope (and thus the acceleration) is:

slope = (4m/s - 2m/s)/(40s - 20s) = (2m/s/20s) = 0.1 m/s^2

The acceleration between 20 seconds and 40 seconds is 0.1 m/s^2

b) The total distance travelled is equal to the area under the curve.

So we could just count the number of squares, this is the easy way.

We can see that each square measures 10 seconds by 1 m/s, then the "area" of each square represents:

a = (10s)*(1m/s) = 10m

This means that each square represents a distance of 10 meters.

We can count that:

between 0s and 10s we have 1 whole square.

between 10s and 20s we have 2 whole squares.

between 20s and 30s we have 2 and half squares.

between 30s and 40s we have 3 and half squares.

Then the total number of squares under the curve is:

1 + 2 + 2.5 + 3.5 = 3 + 2.5 + 3.5 = 3 + 6 = 9

So we have 9 whole squares under the curve, and each square represents a distance of 10 meters, so the total distance traveled is:

Distance = 9*10m = 90m

c) We have an isosceles triangle where we know that one side measures 8.2 cm and another side measures 9.4cm

An isosceles triangle has two equal sides and one different.

So if we want to have the maximum perimeter, the two equal sides must have the longest side length (9.4 cm)

Then the (largest) perimeter of the triangle (the sum of the lengths of all 3 sides) is:

8.2cm + 9.4cm + 9.4cm = 27cm

ok

step-by-step explanation: