Final answer:
The speed at which a 1000 kg car has the same kinetic energy as a 17000 kg truck moving at 21 km/h is approximately 49.2 km/h.
Step-by-step explanation:
The kinetic energy of an object depends on its mass and velocity. The formula for kinetic energy is given by:
KE = (1/2)mv²
Where KE is the kinetic energy, m is the mass of the object, and v is its velocity. To find the speed at which a 1000 kg car has the same kinetic energy as a 17000 kg truck moving at 21 km/h, we can set the kinetic energy of both objects equal to each other:
(1/2)(1000 kg)v² = (1/2)(17000 kg)(21 km/h)²
Simplifying this equation, we find:
v² = (17000 kg)(21 km/h)² / (1000 kg)
v ≈ 49.2 km/h