A spacecraft was designed to assess the ability of an impact to deflect the path of an asteroid. The spacecraft was launched on a rocket. At launch, the rocket has a mass of 555,000 kg and generates a force of 7.6 x 106 N. A. If you were to neglect the effect of gravity, what would the intial acceleration of the rocket be? B. If the acceleration were to remain constant, how fast will the rocket be moving after two seconds? C. As the rocket burns fuel its mass decreases. If the thrust remains the same, how would your answer to part B change? Would the speed after two seconds be lower, the same or higher?

PRACTICE ANOTHER    Q2.   A bag of apples weighs 3.00 lb on Earth. What would it weigh on the Moon, where the free-fall acceleration is one-sixth that on Earth? Give your answer in units of newtons.  N What would it weigh on the surface of Pluto, where g is 0.0673 times that on Earth? Give your answer in units of newtons.  N What is the mass of the bag of apples in kilograms at each of the three locations? Earth kgMoon kgPluto kg

2. A block of mass m is moving with speed v along a horizontal surface when it collides with a uniform rod of mass 2m and length L attached at one end to a pivot. The surface and pivot have negligible friction. The rod is vertical when the block collides with the end of the rod. The block sticks to the rod, and the block-rod system rotates so that the end of the rod reaches a height h, as shown above. The total rotational inertia of the rod about the pivot is 2mL/3. Express answers in parts (a), (b), and (c) in terms of m, L, v, and physical constants as appropriate. 2m, L a. Derive an expression for the angular speed of the block-rod system immediately after the collision. b. Show that the change in height h of the bottom of the rod can be given by the equation A = 3v-/20g. c. Derive an expression for the mechanical energy dissipated during the collision.

A 2.2×104 kg rocket has a rocket motor that generates 2.7×105 N of thrust. Part A What is the rocket's initial upward acceleration? Express your answer with the appropriate units. Part B At an altitude of 5000 m the rocket's acceleration has increased to 7.5 m/s². What mass of fuel has it burned? Express your answer with the appropriate units.

A contestant in a winter games event pushes a 34.0 kg block of ice across a frozen lake as shown in the figure below. The coefficient of static friction is 0.1 and the coefficient of kinetic friction is 0.03. (Assume 8 = 29º.) Calculate the minimum force F (in N) he must exert to get the block moving. N What is its acceleration (in m/s2) once it starts to move, if that force is maintained? m/s²

A cardboard box rests on the floor of an elevator. The box has a mass m = 2.75 kg and the elevator has an upward acceleration of a.   a.  Write an expression for the sum of the forces acting on the box in the y-direction, ΣFy, given that up is the positive y-direction. Your answer should be in terms of FN, m, and g.  b. Write an expression for the normal force, FN, that the block experiences in terms of the elevator's acceleration, the block's mass, and the acceleration of gravity.  c.  If the elevator's acceleration has a magnitude of g in the downward direction, what would the normal force, FN1 be in Newtons?  d.If the elevator's acceleration had a magnitude of g in the upward direction, what would the normal force FN2 be in Newtons?

A 15.0 kg load of bricks hangs from one end of a rope that passes over a small, frictionless pulley. A 28.0 kg counter weight is attached to the other end of the rope, as shown in the figure. You may model the rope as a massless string. The system is released from rest. A. Draw two freebody diagrams, one for the load of bricks and one for the counter weight. B. Find the magnitude of the upward acceleration of the load of bricks. 28.0 kg C. What is the tension in the rope? D. How does the tension compare to the weight of the bricks and the weight of the counter weight? 15.0 kg

Newton's first law states that: Group of answer choices Ia. n the absence of any net force acting on it, a mechanical system is necessarily at rest. b. In the absence of a non-zero net force acting on it, a mechanical system keeps moving in the same direction at the same speed (including the case v=0). c. For any pair A/B of objects interacting with one another, the force of A acting on B is the equal-opposite of the force of B acting on A. d. The rate of change of the velocity of a system is proportional to the net force acting on it.

In the figure below, the net external force on the 28 kg mower is given as 59 N. net If the force of friction opposing the motion is 26 N, what force F (in N) is the person exerting on the mower? (Enter the magnitude.) N Suppose the mower is moving at 1.5 m/s when the force F is removed. How far (in m) will the mower go before stopping?