[填空题]
A ball of mass 1.6 kg is dropped from ks l6ephl -2 e8.7,c1cpzkowia verfou+gm1no 5s;y high building. The only forces acting on the ball are the force of gravity and air resistance. The graph shows the variation of the ve+ 5u1osomnf ;grtical velocity v of the ball with time t.
1.(1)Define terminal speed.
(2)State the terminal speed of the ball.
2.Estimate the vertical displacement of the ball during the 10.0 s of motion.
3.(1)Calculate the instantaneous acceleration of the ball at t= 2.0 s.
(2)Determine the magnitude of the vertical component of air resistance at t=2.0 s. $F_d$ = N
