Answer:
A placebo refers to a substance or treatment that is often used in an experiment but does not have an actual medicinal or experimental benefit.
Explanation:
That's false. If it had only magnitude it would be speed. Velocity also has Direction.
Answer:
Explanation:
Given
angle through which ball is launched
Range of ball=50 m
Range of projectile is 

u=22.136 m/s
If ball is thrown straight upward



s=25 m
(b)For Projectile time of flight is


t=3.19 s
Answer:
121 Joules
6.16717 m
Explanation:
m = Mass of the rocket = 2 kg
k = Spring constant = 800 N/m
x = Compression of spring = 0.55 m
Here, the kinetic energy of the spring and rocket will balance each other

The initial velocity of the rocket is 11 m/s = u.
v = Final velocity
s = Displacement
a = Acceleration due to gravity = 9.81 m/s² = g

The maximum height of the rocket will be 6.16717 m
Potential energy is given by

The potential energy of the rocket at the maximum height will be 121 Joules