Au cours d'un orage le bruit de tonnerre met 7 secondes pour parvenir aux oreilles d'un observateur _1_ à quelle distance est tombée la foudre sachant que dans l'air le son se propage à la vitesse de 340 m/s . _2_ quel est le temps mis par la lumière de l'éclair pour franchir cette distance à l'aide de chronomètre courants

Around faucet handle is part of a(n) a. lever b. screw c. inclined plane d. wheel and axle

Which basic property determines a colored light's placement on the spectrum of visible light? a. speed b. frequency c. amplitude d. velocity

The base of a 50-meter tower is at the origin; the base of a 50-meter tree is at (0, 50, 0). the ground is flat and the z-axis points upward. the following parametric equations describe the motion of six projectiles each launched at time t = 0 in seconds. (i) r (t) = (50 + t2)k (ii) r (t) = 2t2 j + 2t2k (iii) r (t) = 50 i + 50 j + (50 − t2)k (iv) r (t) = 2t j + (50 − t2)k (v) r (t) = (50 − 2t) i + 2t j + (50 − t)k (vi) r (t) = t i + t j + tk (a) which projectile is launched from the top of the tower and goes downward? at time t = , the projectile hits the ground at point (x, y, z) = . (b) which projectile hits the top of the tree?