1. Understand the Concepts

* Kinetic Energy: The energy an object possesses due to its motion. It's calculated using the formula: KE = (1/2) * mv², where:

* KE is kinetic energy (in Joules)

* m is mass (in kilograms)

* v is velocity (in meters per second)

2. Set up the Equation

We know:

* KE = 1.5 x 10⁴ J

* m = 80 kg

We need to find:

* v (velocity)

3. Solve for Velocity

* 1.5 x 10⁴ J = (1/2) * 80 kg * v²

* 1.5 x 10⁴ J = 40 kg * v²

* v² = (1.5 x 10⁴ J) / 40 kg

* v² = 375 m²/s²

* v = √375 m²/s²

* v ≈ 19.4 m/s

4. Convert to km/h

* 1 m/s = 3.6 km/h

* 19.4 m/s * 3.6 km/h/m/s ≈ 70 km/h

Therefore, the speedometer reading is approximately 70 km/h.