Joan sees a stationary long-board 8.0 m in front of her. She decided to run to the long-board as fast as she can, jump on, and roll down the sidewalk. Joan has a mass of 75 kg and the long-board's mass is 25 kg. If Joan accelerates at a steady 1.0 m/s², what is the magnitude of the velocity of the long- board just after Joan jumps and lands on it?

A rocket has total mass Mi = 360 kg, including Mfuel = 330 kg of fuel and oxidizer. In interstellar space, it starts from rest at the position x = 0, turns on its engine at time t = 0, and puts out exhaust with relative speed ve = 1 500 m/s at the constant rate k = 2.50 kg/s. The fuel will last for a burn time of Tb = Mfuel/k = 330 kg/(2.5 kg/s) = 132 s. (a) Show that during the burn the velocity of the rocket as a function of time is given by v(t)=veln(1ktMi) (b) Make a graph of the velocity of the rocket as a function of time for times running from 0 to 132 s. (c) Show that the acceleration of the rocket is a(t)=kveMikt (d) Graph the acceleration as a function of time. (c) Show that the position of the rocket is x(t)=ve(Mikt)ln(1ktMi)+vet (f) Graph the position during the burn as a function of time.

A 81.4 kg toy rocket is sent flying straight up into the air with an acceleration of 4.20 m/s2. After 4.70 s it explodes and breaks apart into two pieces. The heavier piece has a mass of 66.0 kg. If the lighter piece is able to reach a maximum height of 168 m above the ground, what is the speed of the heavier piece of the toy rocket just after the explosion?

You are sitting in a sled, at rest on a pond covered with nice, thick, frictionless ice. Your own mass is 76.3 kg, and the sleds mass is 10.8 kg. The sled is moving by itself on the ice at 3.07 m/s. You parachute vertically down onto the sled, and land gently. What is the sleds velocity with you now on it?     0.49 m/s     0.44 m/s     0.38 m/s     0.23 m/s

A 50-kg girl is standing on a 139-kg plank. The plank, originally at rest, is free to slide on a frozen lake, which is a flat, frictionless surface. The girl begins to walk along the plank at a constant velocity of 1.64 m/s to the right relative to the plank. What is the velocity of the plank relative to the ice surface? Submit Answer Tries 0/10

Identical twins, each with mass 62.0 kg, are on ice skates and at rest on a frozen lake, which may be taken as frictionless. Twin A is carrying a backpack of mass 12.0 kg. She throws it horizontally at 2.80 m/s to Twin B. Neglecting any gravity effects, what are the subsequent speeds of Twin A and Twin B? Twin A     m/s Twin B     m/s

Identical twins, each with mass 53.5 kg, are on ice skates and at rest on a frozen lake, which may be taken as frictionless. Twin A is carrying a backpack of mass 12.0 kg. She throws it horizontally at 3.15 m/s to Twin B. Neglecting any gravity effects, what are the subsequent speeds of Twin A and Twin B?

Dan is gliding on his skateboard at 3.96 m/s. He suddenly jumps backward off the skateboard, kicking the skateboard forward at 7.47 m/s. How fast is Dan going as his feet hit the ground? Dan's mass is 64.07 kg and the skateboard's mass is 4.92 kg.

Identical twins, each with mass 47.0 kg, are on ice skates and at rest on a frozen lake, which may be taken as frictionless. Twin A is carrying a backpack of mass 12.0 kg. She throws it horizontally at 2.70 m/s to Twin B. Neglecting any gravity effects, what are the subsequent speeds of Twin A and Twin B? Twin A m/s Twin B m/s Need Help? Read It

A 128 kg astronaut and his equipment are initially at rest. To move forward with a velocity of 2.34 m/s, the astronaut fires a 532 N rocket in the backward direction. How long does the astronaut need to fire the rocket?