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MECHANICS

Newton's First Law of Motion: Inertia

Linear Motion

Newton's Second Law: Force and Acceleration

Newton's Third Law: Action and Reaction

Momentum

Energy

Rotational Motion

Gravity

Projectile and Satellite Motion

Energy

Kinetic and potential energy; work and the conservation of energy.

Initial angle (°)

60°

String length (m)

1.8

Bob mass (kg)

1.5

Energy (J)

PE

13.24 J

KE

0.00 J

E_mech

13.24 J

E_th (thermal)

0.00 J

E_total

13.24 J

Energy distribution

Energy vs. Time

Energy transformation

At the highest points (A, C): PE is high, KE is low.

At the lowest point (B): KE is high, PE is low.

Air resistance (drag) opposes motion and turns mechanical energy into thermal energy.

Total energy stays constant (mechanical + thermal).

Equations

Energy

PE=mghPE = m g h

PE = 1.5 × 9.81 × 0.90 = 13.24 J

KE=12mv2KE = \frac{1}{2} m v^2

KE = 0.5 × 1.5 × (0.00)² = 0.00 J

Mechanical Energy

Emech=PE+KEE_{\mathrm{mech}} = PE + KE

E_mech = 13.24 + 0.00 = 13.24 J

Total Energy

Etotal=PE+KE+EthE_{\mathrm{total}} = PE + KE + E_{\mathrm{th}}

E_total = 13.24 + 0.00 + 0.00 = 13.24 J (constant)

Etotal=constantE_{\mathrm{total}} = \text{constant}

Height Definition

h=ylowestyh = y_{\mathrm{lowest}} - yPE=mg(ylowesty)PE = m g (y_{\mathrm{lowest}} - y)

h = 0.90 m

Energy changes between potential and kinetic.

Air resistance converts mechanical energy into thermal energy.

Total energy remains constant.