[单选题]
A jet fighter plane is launched from a catapult on an aylb h5(m ;2w8da xdi8tircraft carrier. It rev)*d3-bl9 j u1vbsvwu aches a speed of 42 m/s at the end of the catapult, and this requires 2.0 s. Assuming the acceleration is constant, whatwvbv 3lvb- *d)u1u9 sj is the length of the catapult?