The height of the ball when lifted is given by 7sin(25)=2.96
the gravitational energy is mgh, the kinetic is (1/2)mv². We can set these equal since the pendulum doesn't lose much energy
mgh = (1/2)mv²
we can divide by m (since we don't have it anyways)
gh = v²/2
v=√(gh/2) = √(9.81*2.96/2)=3.8m/s.
Not exactly one of your choices, but the right one none the less
Answer:
Commutator is a ring which reverse the direction of current in AC circuit so that the coil connected to it will continuous to move in the same direction.
Explanation:
In motors there exist a coil which is rotated due to torque of magnetic field when current flow through it. Since AC current is used to run the motor so we know that AC current changes its direction after half cycle.
So here commutator plays an important role to reverse the direction of current after every half cycle so that the current goes in same direction always into the coil.
This will produce a constant direction torque on the coil so that it will rotate in same sense always.
So commutator role is to provide same direction current to the coil by reversing its direction after every half cycle
It will tend to follow a trajectory path. When a projectile is being flung or flown away by a certain type of force, the trajectory is what it follows through the means of both force and function of time itself. It's also called as flight path.
You can find
1) time to hit the ground
2) initial velocity
3) speed when it hits the ground
Equations
Vx = Vxo
x = Vx * t
Vy = Vyo + gt
Vyo = 0
Vy = gt
y = yo - Vyo - gt^2 / 2
=> yo - y = gt^2 / 2
1) time to hit the ground
=> 8.0 = g t^2 / 2 => t^2 = 8.0m * 2 / 9.81 m/s^2 = 1.631 s^2
=> t = √1.631 s^2 = 1.28 s
2) initial velocity
Vxo = x / t = 6.5m / 1.28s = 5.08 m/s
3) speed when it hits the ground
Vy = g*t = 9.81 m/s * 1.28s = 12.56 m/s
V^2 = Vy^2 + Vx^2 = (12.56 m/s)^2 + (5.08 m/s)^2 = 183.56 m^2 / s^2
=> V = √ (183.56 m^2 / s^2) = 13.55 m/s
Answer:
Explanation:
A simple light microscope uses light for imaging of objects where as a transmission electron microscope uses a monochromatic beam of electrons.
This beam is passed by a magnetic field which is very strong and thus act as a lens.
Its resolution of very high which is about 0.2 nanometers because of the separation between two atoms.
Because of this reason its resolution is about 1000 times greater than light microscope.
