### A measurement of the local gravitational acceleration.

Watch The Video:

Teachable Topics:

• Newton's Laws
• Acceleration
• Gravity

Theory:

A body of mass will fall at a constant acceleration due to the attraction of mass between the body and the mass fo the earth. If the acceleration is labeled g, then we can write:

F = mg

where m is the mass and F is the force the earth exerts on it.

Since acceleration is the result of the change in velocity (Δv) with the passage of time (Δt),

Apparatus:

• Ruler
• 12V DC power supply
• Photogate
• steel ball
• Three clamps
• Vernier caliper
• Scissor jack
• Electromagnet
• Alignment string
• Four connecting wires

Procedure:

• Once the equipment is clamped in place, align the photogate with the electromagnet. This is done using an alignment string, which hangs from the electromagnet, (See photo).
• After it is aligned, remove the string, and adjust the strength of the electromagnet so the metal ball is hanging from the top.
• Then reset your photogate before dropping the ball through.
• Repeat this three times, adjusting the height each time.