A forensic scientist test-fires a projectile (mass mP) at a cubic block (volume V), made from wood (density D), resting on a rough surface (static = kinetic coefficient uS). The bullet enters the block with an initial velocity vO and exits the block with a velocity v1. The friction forces on the bullet as it passes through the length of the block are unknown and are assumed to be constant. Solve these problems algebraically first: a) What is the deceleration of the bullet inside the block? How many "g" is that? b) How much time does it take the projectile to pass through the block? c) What is the velocity of the block as the bullet exits? d) How long (time) and how far (distance) does the block slide after the bullet has exited? e) Solve the above numerically for the following parameters (g =9.81m/s^2): mP = 10g, V = 0.1m^3, D = 500kg/m^3, µS = 0.8, v0 = 500m/s, v1 = 100m/s %3D

Physics 121 Spring 2021 - Document #11: Homework #04 & Reading Assignment page 4 of 8 Problem 1: Gnome Ride - This from a Previous Exam I. A Gnome of given mass M goes on the Gnome Ride as follows: He stands on a horizontal platform that is connected to a large piston so that the platform is driven vertically with a position as a function of time according to the following equation: y(t) = C cos(wt) Here w is a constant given angular frequency, C is a given constant (with appropriate physical units) and y represents the vertical position, positive upward as indicated. Part (a) - What is the velocity of the Gnome at time t = 0? Explain your work. Present your answer in terms of the given parameters Part (b) – What is the net force on the Gnome at time t = 0? Explain your work. Present your answer in terms of the given parameters Part (c) – What is the Normal Force on the Gnome at time t = 0? Explain your work. Present your answer in terms of the given parameters Some Possibly Useful…

What factor(s) do you think affected the aftermath of the collision for set-up 4 considering the marbles have the same mass?

Data has been gathered from a lifting system used to transport engine parts. The system consists of a drum and cable. The following data was obtained when the drum lowers the load (assume constant acceleration). Drum diameter = 0.8m Mass of load = 3kg Initial velocity = 0 m/s Time to descend = 0.5 secs Distance travelled = 0.25m You have been asked to use this information to determine: The final linear velocity of the load The linear acceleration of the load The final angular velocity of the drum The angular acceleration of the drum The tension force in the cable The torque applied to the drum   In determining the above quantities, you should clearly state the formulae used and apply dimensional analysis techniques to show that all values/units used are homogeneous.   From the formulae used (above) you should apply dimensional analysis techniques to develop two equations for power (in terms of linear velocity and angular velocity).

Find the velocity at point B for each of them

A ring of mass m is attached to the spring and slides over the rod. Unextended length of the spring l0 and the spring coefficient is k. When the collar is at point C, it is released and between the collar and bar Since the coefficient of friction is μk; a) Find the velocity of the ring at points A and B using the Work-Energy method.  b) Find the normal forces acting on the collar at points A and B.

A 250 g ball collides with a wall. The figures below show the ball’s velocity and force exerted on the ball by the wall. What is vfx, the final velocity of the ball? Paste the completed Bar Chart below. 1. identify the system 2. draw a quick sketch of the initial state of the object(s) 3. do a momentum bar chart

Bonus Question: 8 Extra points A block of mass m = 1.0 kg is dropped from height h= 75cm onto a spring. The mass will attache to the spring and then the spring will compress. a). Find the spring constant if the maximum distance the spring is compressed is 10cm in following arrangement? ០០០០០០០០០ b). Find the maximum distance the spring is compressed in following arrangement if the angle is 30 degrees? You are using same spring. ss. mmmm 8

1) Is it possible to prescribe the velocity v0, so that the pendulum keeps rotating with alpha = pi/2 Explain clearly why?  Given: L, g, and m. 2) After transient motion, the pendulum settles at steady state rotation atalpha = pi/3. Find the initial velocity v0. Given: L, g, m, sin(pi/3) = (squareroot(3)/2), cos(pi/3) = (1/2). [Hint: Use the conservation of energy and the 2nd Newton’s law.]

A boxer delivers a hard blow to the chin of his opponent. The inertia of the boxer's hand (with glove) and forearm is 3.0 kg, and the inertia of the opponent's head is 6.5 kg. You learned in neurobiology class about 10 J of extra internal energy will render an opponent wobbly - kneed, and you guess that about half of the converted energy will end up in the opponent's head. Assuming a coefficient of restitution e = 0.20, with what speed does the boxer's fist have to contact the opponent's head in order to deliver the punch?