Motion
A car starts from rest and accelerates at a constant rate of 2 m/s for 5 seconds.
a. What is the cars final velocity?
b. How far does the car travel during this time?
t = 5s, distance traveled = 25 meters
A 5 kg box is pulled across the floor with a force of 30 N. The frictional force is 10 N.
a. What is the net force on the box?
b. What is the acceleration of the box?
net force: 30 - 10 =20 N
acceleration: 20/ 5= 4 m/s
A 3kg cart moving at 4 m/s collides dead on with a 2kg cart at rest. The carts stick together.
A. What is the velocity of the combines carts after the collision?
Hint: Find total momentum of both objects before collision then compare it to total momentum of their total mass.
The velocity after collision; 2.4 m/s
How many total students are in Honors Physics?
30
A soccer ball is kicked from rest with a constant acceleration of 3 m/s 2 on a flat field.
a. What is the velocity of the ball after 4 seconds?
b. How far does the ball travel in that time?
c. If the ball continues at the velocity is reached at 4 seconds, how far will it travel after 3 more seconds?
velocity after 4 seconds: 12 m/s, distance traveled during acceleration : 24m, distance traveled at a constant velocity; 36 m
A book is lying on the table. A student gently pushes it, but it doesn’t move.
a. Why doesn’t the book move immediately?
b. What must happen in order for the book to start moving?
A: the book doesn’t move because the push was too small to overcome the friction between the book and the table.
B: to make the book move, the student must apply a force bigger than the frictional force
A 2kg ball is moving to the right at 5 m/s.
A. 2 x 5 =10 10kgm/s (right)
This sport came up the most during our concussion and CTE discussions.
Football
A cyclist is moving at initial velocity of 4 m/s when they being accelerating at a constant rate of 1.5 m/s for 6 seconds,
a. What is the cyclist final velocity?
b. How far does the cyclist travel during the 6 seconds?
c. If the cyclist continues for 4 more seconds, what is the total distance traveled?
final velocity= 13 m/s, distance during acceleration= 51 meters, total distance= 103m
a 2kg toy car is pushed with a force of 10 N on a frictionless surface.
a. What is the acceleration of the car?
b. If the car is instead 4kg and the same force is applied, what is the acceleration?
for A, m: 2 kg
a: 10/2 =5 m/s2
for B, m: 4kg
a: 10/4=2.5 m/s2
The acceleration decreases as mass increases if force is constant.
A 2kg cart moving to the right at 5 m/s collides with a 3 kg cart at rest. They stick together.
What is the velocity after collision?
Hint: Find total momentum of both objects before collision then compare it to total momentum of their total mass.
2 kg m/s
What is Mr. Russell's biggest pet peeve with Honors Physics?
Class of yappers. (talks a lot)
DAILY DOUBLE!!!!!
A train is traveling at 20 m/s when the engineer steps on the breaks, causing the train to slow down at constant rate of 2 m/s 2
a. How long does it take for the train to come to a complete stop? (time and distance)
b. What is the trains average velocity during the braking process?
time to stop: 10 seconds, Distance traveled: 100 meters, average velocity 10 m/s
A small hover rams has the mass of 80kg and it’s floating on a frictionless ice surface. The hovercraft also has a cannon than can fire a kg ball at the speed of 20 m/s.
A. Identify the action reaction pair of forces involved in the canon firing,
c. Explain why the hovercraft moves even though there’s no friction.
Actions reaction: Conor pushes ball forward/ Ball pushes canon backward.
Why???
The hovercraft moves due to the reaction force, no friction is needed to cause motion.
A 4kg ball moves at 3 m/s and a 2kg ball moves at -1m/s. What is the total momentum?
4 x 3 + 2 x (-1)= 12 - 2 = 10 kgm/s (right)
What are the core laws of Physics and who discovered them (need to include first name)?
A 20kg box sits on the flatbed of a truck. The truck accelerates at 2 m/s 2. The surface of the truck bed is smooth, but there’s some friction between the box and the flatbed the coefficient of static friction between the box and bed is 0.3.
A. Determine where the box slides on the truck bed.
B. If the truck suddenly stops, explain what happens to the box according to Newtons 1st Law.
C. Identify an action- reaction force pair that happens between the box and the truck.
A. The box will stay in place. B. The box will keep moving forward if the truck stops; due to inertia. C. Then truck friction on the box, the box friction on the truck bed.
A 20kg box sits on the flatbed of a truck. The truck accelerates at 2 m/s 2. The surface of the truck bed is smooth, but there’s some friction between the box and the flatbed.
A. Determine where the box slides on the truck bed.
B. If the truck suddenly stops, explain what happens to the box according to Newtons 1st Law.
C. Identify an action- reaction force pair that happens between the box and the truck.
A. The box will stay in place.
B. The box will keep moving forward if the truck stops; due to inertia.
C. The truck bed applies friction on the box, the box friction on the truck bed.
A 5 kg cannon fires two 0.5 kg cannonballs in opposite directions at 20 m/s each.
What is the recoil velocity of the cannon?
The cannon doesn’t move because the cannonballs cancel each other’s momentum.
No one! (keep it that way)