A roller coaster cart of mass 450 kg is launched from rest at ground level by an electromagnetic launcher.
The launcher inputs 1.20 × 105 J of electrical energy. As the cart leaves the launcher, it has climbed to a height of 5.0 m and is moving at a speed of 18 m s-1, as shown in the diagram below.
How much energy is wasted as thermal energy and sound during the launch? (Take g=9.81 m s−2g = 9.81\text{ m s}^{-2}g=9.81 m s−2)
2.5×104 J2.5 \times 10^4\text{ J}2.5×104 J
4.7×104 J4.7 \times 10^4\text{ J}4.7×104 J
9.5×104 J9.5 \times 10^4\text{ J}9.5×104 J
9.8×104 J9.8 \times 10^4\text{ J}9.8×104 J