Hey guys! Can I please have some please with these two questions? Any explained working out would be really helpful. Thanks!
Sidzeman is right! a simple substitution! If you need further help, I'll be happy to!
20) This will be a bit tricky to explain, but it uses triangles!!
It is launched horizontally, so the initial VERTICAL acceleration is 0. We also know the Horizontal velocity is constant.
Knowing that after 2 seconds, the angle is 45 degrees, we know that this triangle in ISOSCELES, which means that the horizontal AND vertical components have to be the same!
As we know gravitational acceleration is a constant 9.8 PER SECOND, after TWO seconds, the vertical velocity of the ball is:
9.8 X 2 = 19.6
And as we know the horizontal and vertical velocities HAVE to be equal, it means the horizontal velocity is ALSO 19.6.
The find the resultant velocity, we must find the hypotenuse so
(19.6)^2 + (19.6)^2 = v^2
v = 27.72
Which is D!!