Mechanics | Relativity Answers

A ball thrown up from a rooftop of height 54m lands on the ground in 5s. What is its speed 13m below?

Purpose:

The purpose of this activity is to determine the acceleration of a falling object, through manual measuring and graphing techniques, using the object’s position at various times.

Table 1 – Object’s Position

Time (s) position (m(down))

0.0 0.50

2.0 0.70

4.0 1.00

6.0 1.25

8.0 1.60

10.0 2.00

Instructions:

1. Plot the points above into a position-time graph.

2. Draw a curved line-of-best-fit through the plotted points.

3. Draw a minimum of 3 tangents and determine the slope for each. Show all calculations and include units.

4. Create a new table of values using time and instantaneous velocity as the variables.

5. Plot these points into a velocity-time graph and draw a best fit line.

6. Determine the slope of the line and show all work.

7. Draw a third graph showing the acceleration of the vehicle for 10 seconds. Shade the area under the line.

Discussion:

1. What was the graphically determined acceleration?

2. Calculate the area under the line of the V-T and A-T graph and indicate what it represents.

3. What are the limitations of using this technique for determining acceleration?

(need to do the instructions part and discussion part)

A 500g uniform sphere of 7cm radiud ppins at 30 rev/sec on an axis through its center

Find it's kinetic energy rotational

 A sleigh ride takes place on an even, inclined, straight toboggan run with a gradient of 3: 100. The sled with its crew has a mass of m = 80 kg and a coefficient of sliding friction of u = 0.025. After a short push, the static friction is overcome and an evenly accelerated movement begins.

 1) Calculate the downhill force, the frictional force and the resulting acceleration a, of the slide.

 (3 P.) 2) After a time and a covered distance of s, the slide reaches a speed of Vmax = 40 km / h. Calculate, and s ,.

 (3 P.) 3) The sledge is braked so that it continues to toboggan for 667 m. Calculate the required time t,. The slide is then braked evenly for 30 s until it comes to a standstill. It covers a distance of sz with a constant braking deceleration ag. Calculate są and az as well as the total length and total time of the toboggan run.

 (9 P.) 4) Make sketches with inscription of the speed-time-diagram and the distance-time-diagram. Choose suitable scales yourself!

 (4 p.)

Opposite: Beam with pipe cross-section R = 40 mm, r = 38 mm, a = 1 m, structural steel (R. = 235 MPa),

 p = 7.85 kg / dm3, E = 210000 MPa At the end of the pipe there is a mass m hanging on a rope.

 g = 9.81 m / s2

 - 2r 2R

 Ges .: a) Calculate the maximum, taking into account the weight of the pipe

 permissible mass must so that the stress analysis for bending for the pipe is still fulfilled.

 (14 p.)

 b) Give the resulting bending line and the maximum bending deflection for the

 Pipe at mui. The weight of the pipe itself must be taken into account and the coefficients must be calculated before the expressions in brackets.

Air flows through a heating duct with a square cross-section with 9-inch sides at a speed of 5.7 ft/s. Just before reaching an outlet in the floor of a room, the duct widens to assume a square cross-section with sides equal to 13 inches. Compute the speed of the air flowing into the room (in ft/s), assuming that we can treat the air as an incompressible fluid.

A uniform pole 7m long weighs 10kg is supported by a boy 2m from one end and a man 3m from the other end. At what point must a 20kg weight be attached so that the man would support thrice as much weight as the boy

You are pushing your desk with a constant force of 80 N for 30 seconds to move it across the room. What is your impulse?

A ball is thrown straight upward with a speed, v from a point, h meters above the ground. Show that the time taken, t for the ball to strike the ground is t= (v/g)[1+√1+(2gh/v^2)]