Topic 2: Mechanics. Kinematics. What is gravity? Where does it come from? What kinds of things have gravity? I have two masses. One is a basketball. The other is a 5lb bag of potatoes. If I hold them at the same height and drop them at the same time, which one hits the ground first?
Avg Velocity = Displacement / time
Instantaneous velocity = velocity at given moment.
ex. Initial velocity, final velocity.
1)Convert the following speeds into m/s.
a) A car travelling at 100 km/h
b) A runner running at 20 km/h
3)Calculate the final velocity of a body that starts from rest and accelerates at 5m/s for a distance of 100m.
4)A body starts with a velocity of 20m/s and accelerates for 200m with an acceleration of 5m/s. What is the final velocity of the body?
5)A body accelerates at 10m s-2 reaching a final velocity of 20m s-1in 5s. What was the initial velocity of the body?
6) A ball is thrown upwards with a velocity of 30m/s. What is the displacement of the ball after 2s?
7) A ball is dropped. What will its velocity be after falling 65cm?
8) A ball is thrown upwards with a velocity of 20m/s. After how many seconds will the ball return to its starting point?
The object moved toward the right, stopped and returned to its starting position.
Use the graph and your understanding of slope calculations to determine the acceleration of the rocket during the listed time intervals.
Describe the motion depicted by the following velocity-time graphs. In your descriptions, make reference to the direction of motion (+ or - direction), the velocity and acceleration and any changes in speed (speeding up or slowing down) during the various time intervals (e.g., intervals A, B, and C).
The object moves in the + direction at a constant speed - zero acceleration (interval A). The object then continues in the + direction while slowing down with a negative acceleration (interval B). Finally, the object moves at a constant speed in the + direction, slower than before (interval C).
Consider the velocity-time graph below. Determine the acceleration (i.e., slope) of the object as portrayed by the graph.
The acceleration (i.e., slope) is 4 m/s/s. If you think the slope is 5 m/s/s, then you're making a common mistake. You are picking one point (probably 5 s, 25 m/s) and dividing y/x. Instead you must pick two points (as in the discussed in this part of the lesson) and divide the change in y by the change in x.
Determine the displacement of the object during the time interval denoted by the shaded area.
A car (A) moves to the left with speed 40km/h (with respect to the road). Another car (B) moves to the right with speed 60km/h(also with respect to the road). Find the relative velocity of B with respect to A.
A rain drop falling through air reaches a terminal velocity before hitting the ground. At terminal velocity, the frictional force on the raindrop is
A car is travelling along a level highway at a constant velocity in a straight line. Air resistance is not negligible. Draw the free-body diagram for this car.
An elevator of mass 800kg is supported by a thick metal rope capable of withstanding a tension of 1200N. Calculate the tension in the rope when the elevator is:
A man pushes a car along a road. He exerts a force F on the car. In this situation, what is the equal and opposite force to F as referred to in Newton’s third law?