To Find :
Position vector at time
and
.
Solution :
r (t) = 2 (t −7)i + 12t j
Putting t = 5 s and t = 8 s, we get :
r(5) = 2( -2 )i + 60j
r(5) = -4i + 60j
r(8) = 2i + 96j
Now, to find speed differentiating the r(t) w.r.t t :

Hence, this is the required solution.
Answer: 91 coins
9 x 25 = 2.25 dollars
3 x 10 = 30 cents
1 x 5 = 5 cents
Answer:
x = 27, and y = 47.
Step-by-step explanation:
AB is a line, so the measures of the angles measuring
2x + 1, 3x + 10, and 8/9 x + 10
add to 180 degrees. We can use that fact to find x.
2x + 1 + 3x + 10 + 8/9 x + 10 = 180
Add like terms on the left side except for the faction.
5x + 8/9 x + 21 = 180
Multiply both sides by 9.
45x + 8x + 189 = 1620
Add like terms on the left side. Subtract 168 from both sides.
53x = 1431
Divide both sides by 53.
x = 27
The angle measuring 3x + 10 is vertical with the angle that is made up of the measures y - 3 and y. Therefore, the sum of the measures y - 3 and y equals the measure 3x + 10. We know x, so we can find 3x + 10.
3x + 10 = 3(27) + 10 = 91
Now we set the sum of y - 3 and y equal to 91 and solve for y.
y - 3 + y = 91
2y - 3 = 91
2y = 94
y = 47
x = 27, and y = 47.