A projectile is launched from ground level at an angle of 30 degrees above the horizontal. Neglect air resistance and consider the motion from just after the moment it is launched to just before the moment it lands on the ground. When does the projectiles velocity equal its launch velocity?

At the highest point.
The projectile's velocity is never equal to its launch velocity after launch.
The projectile's velocity is always equal to its launch velocity.
Just before landing on the ground.
Halfway back to the ground.
Halfway to the highest point.

The projectile's velocity is never equal to its launch velocity after launch.

Explanation:

This is a tricky question, and the difference between the speed and the velocity should be clarified.

The velocity is a vector and the speed is a scalar quantity, which is basically the magnitude of velocity.

The projectile's initial velocity has a direction (30° above horizontal) and a magnitude. This magnitude is equal to its speed just before landing on the ground, however this is not equal to its velocity, because this time the direction is towards the ground. Therefore, the velocity of the projectile is never equal to its launch velocity.

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

ill do it for 100, also this isnt 80 its 40