physics final g10 2023 term2

Velocity

..................... is defined as the rate at which an object changes its position.

displacement

.......................is the difference between the final position and initial position.

Distance

.......................is the total path length traveled from one location to another.

500km/h north

125 km north in ¼ h?

vi= 25m/s a= -4m/s^2 t=5 we are looking for vf so we will use (vf=vi+at) vf= 25 - 4x5 = 25-20 vf= 5m/s

A bicyclist is traveling at +25 m/s when he begins to decelerate at -4 m/s2. How fast is he traveling after 5 seconds?

we will use (a= vf-vi / t AND s=d/t) first we will find the time 7 = 35 / t (multiply by t to take it to the other side) 7t = 35 (now divide by 7) t= 35/7 OR 5s now lets find the acceleration a= 7-0 / 5s a= 7/5 OR 1.4 m/s^2

A bike accelerates uniformly from rest to a speed of 7 m/s over a distance of 35 m. Determine the acceleration of the bike.

c. Acceleration = 2m/s2

A body moves in an increasing speed of 2m/s for every second which of the following is true? A. Total distance=2m B. Velocity=2m/s c. Acceleration = 2m/s2 D. Total time=2s

F) -6 m/s^2 (6-24 / 3 = -18 / 3 = -6 m/s^2)

A bus starting from a speed of +24 m/s slows to 6 m/s in a time of 3 s. The average acceleration of the bus is A) 2 m/s^2 B) 4 m/s^2 C) 6 m/s^2 D) -2m/s^2 F) -6 m/s^2

b. 10 seconds

A car accelerates at 2 m/s^2 Assuming the car starts from rest, how much time does it need to accelerate to a speed of 20 m/s? a. 2 seconds b. 10 seconds c. 20 seconds d. 40 seconds e. none of the above

first we will turn km into m and h into s 90/1 x 1000/60x60 ----> 25 m/s (vi) 120/1 x 1000/60x60 ---->33.3 m/s(vf) half a minute -----> 30s (t) we want to find acceleration so we will use (a = vf-vi/t) a= 33.3 - 25 / 30 (plug into calculator) a= 0.27 m/s^2

A car changes its velocity from 90 km/h into 120 km/h in half a minute, find its acceleration in m/s?.

vi=0 a= 21-0/7 =3m/s^2 (because a = change in velocity/time) t=2 we are looking for vf so we will use (vf=vi+at) vf= 0 + 3x2 = 6 vf= 6 m/s

A car starts from rest and accelerates uniformly to reach a speed of 21 m/s in 7.0 s. What was the speed of the object after 2.0 seconds?

c. 6 m/s^2 (42-0/7 =42/7 =6m/s^2)

A car starts from rest and after 7 seconds it is moving at 42 m/s. What is the car's average acceleration? a. 0.17 m/s^2 b. 1.67 m/s^2 c. 6 m/s^2 d. 7 m/s^2 e. none of the above

distance: 8m displacement: 3m

A dog moves from point A (1) to point to point C (5), then back to point B(3) along the line shown in the figure . what is the distance and what is the displacement.

vi= 90km/h ----> 25m/s reaction time= 0.75s a= -10 vf=0 (because he hit the breaks the car will eventually stop at 0) we want to find (xf-xi) or delta (x) without using time because we dont have it so { vf^2=vi^2 + 2a x (xf-xi or delta x)} 0^2 = 25^2 + 2 x -10 x delta (x) 0= 625 -20(vf-vi) (divide each side by -20(vf-vi) to take it to the other side) 20(vf-vi) = 625 (divide 20 on both sides so we can get delta (x) alone) (vf-vi) = 625/20 or 31.25m (now we have to calculate the reaction time using d=vt) d= 25 x 0.75 (reaction time) d= 18.75 m (now we add both of the distances together to see if its > or < than 40m) 31.25 + 18.75 = 50m (which means she hit the barrier. very tragic :c)

A driver of a car going 90 km/h suddenly sees the lights of a barrier 40.0 m ahead. It takes the driver 0.75 s before he applies the brakes (this is known as reaction time). Once he does begin to brake, he decelerates at a rate of 10.0 m/s?. a) Doe she hit the barrier?

d) 4 km/h

A gazelle travels 2 km in a half hour. The gazelle's average speed is a) 1/2 km/n. b) 7 m/n. c) 2 km/h. d) 4 km/h

D) 2.5 m/s^2 (20-0 / 8 = 20/8 = 2.5m/s^2)

A motorcycle starts from rest and accelerates to a speed of 20 m/s in a time of 8 s. What is the motorcycle's average acceleration? A) 160 m/s^2 B) 80 m/s^2 C) 8 m/s^2 D) 2.5 m/s^2 E) 0.4 m/s^2

we will use (vf^2 = +vi^2 2a x

A plane has a takeoff speed of 88 m/s and requires 1365 m to reach that speed. Determine the acceleration of the plane and the time required to reach this speed, if it started from rest.

we will use (x= vi x t + 1/2 x a x t^2 AND a= vf-vi / t) a= 40-19 / 3 a= 7 m/s^2 then x= 19(3) + 1/2 x 7 x (3^2) PLUG INTO CAL x= 88.5 m

A race car accelerates uniformly from 19 m/s to 40 m/s in 3 seconds. Determine the acceleration of the car and the distance traveled.

vi= 76m/s a= -9m/s^2 t= 4s we are looking for vf so we will use (vf=vi+at) vf= 76 -9 x 4 = 76 - 36 vf= 40 m/s

A race car is traveling at +76 m/s when is slows down at -9 m/s2.for 4 seconds. What is his new velocity?

B. 8(use a= vf-vi/t --> a= 36-4/4 = 8

A racing car increases its velocity (speed) from 4m/s into 36m/s in a time interval =4s the acceleration of the car in m/s2 unit equals? A. 7 B. 8 C. 9 D. 10

(vf = vi +at) vf = 0 + 2m/s x 2s vf=4

A skateboarder starting from rest accelerates down a ramp at 2 m/s? for 2 s. What is the final speed of the skateboarder(lemme check)?

constant velocity

A straight line on a position-time graph represents motion with ......... velocity.

E) 80 m/s (4m/s^2 x 20s = 80 m/s)

A train accelerates from rest with an acceleration of 4 m/s^2 for a time of 20 s. What is the train's speed at the end of 20s? A) 0.25 m/s B) 4 m/s C) 2.5 m/s D) 0.8 m/s E) 80 m/s

a. 0m/s^2. (6-6 / 3s = 0/3 = 0 acceleration)

A train travels 6 meters in the first second of travel, 6 meters again during the second second of travel, and 6 meters again during the third second. Its acceleration is a. 0m/s^2. b. 6 m/s^2. c. 12 m/s^2. d. 18 m/s^2 e. none of the above

d. all of the above

A vehicle undergoes acceleration when it а.gains speed. b. decreases speed. C. changes direction. d. all of the above

slow down

Acceleration against velocity means

change directions

Acceleration at an angle to velocity means

speed up.

Acceleration in the direction of velocity means

c. the rate at which velocity itself changes

Acceleration is defined as a. the rate at which distance is cover b. the rate at which an object freely falls from rest c. the rate at which velocity itself changes d. the distance an object has fallen.

d) velocity divided by the time interval.

Acceleration is defined as the CHANGE in a) time it takes to move from one place to another place. b) velocity of an object. c) distance divided by the time interval. d) velocity divided by the time interval. e) time it takes to move from one speed to another speed.

A. greater than(use a=vf-vi/t and compare)

Car A changed its velocity from 10m/s into 30m/s in 4 s, and car B changed its velocity from 22m/s to 33m/s in 11s. The acceleration of car A is .........• acceleration of car B. A. greater than B. less than C. equals D. half

a) constant velocIty.

Constant speed in a constant direction is a) constant velocIty. b) constant acceleration c) instantaneous speed d) average velocity

steady speed

Constant speed means

Speed and Direction

Constant velocity means both constant

Vector

Displacement is a ..................quantity, as it has both direction and magnitude.

B. position

Displacement represents a change in..............of a body in a certain direction. A. motion B. position C. Speed D. Acceleration

scalar

Distance is a .................quantity, it has no direction, only magnitude.

vi= 4 a=2 t=3 we are looking for vf so we will use (vf=vi+at) vf= 4 + 2x3 =4+6 vf= 10m/s

Georgia is jogging with a velocity of 4 m/s when she accelerates at 2 m/s for 3 seconds. How fast is Georgia running now?

speed is scalar while velocity is a vector

How is velocity different from speed?

500km/ north

If an airplane travels 500 km due north in 1 h, what is its velocity?

500km/h north

If it ravels 250 km due north in ½ h?

acceleration

If the velocity of the particle changes at a constant rate, then this rate is called the constant........................

truck--> 15-0 / 5 = 15/5 = 3km/h^2 car---> 65-50/5 = 15/5 = 3km/h^2 they both have the same acceleration (use acceleration formula that you memorized :D )

In 5 seconds a car moving in straight line increases its speed from 50 km/h to 65 km/h, while a truck goes from the rest to 15 km/h in a straight line. Which undergoes greater acceleration? What is the acceleration of each vehicle?

we will use because we want to find Vf (vf=vi+at) vf= 4 + 2 x 2 vf= 4+4 vf=8 m/s

Let t be the time in seconds from the beginning of the motion of a particle. If the particle has a velocity of 4 m/s initially (at t=0) and has a constant acceleration of 2 m/s2 , find the velocity of the particle is at t=2:

an object's position / elapsed time

On a position-time graph the rise corresponds to the ......... and the run to the ..........

y , x

On a position-time graph, position data are plotted on the .... axis; time data are plotted on the .... axis.

m/s

SI unit of velocity is

c. entirely different concepts.

Speed and acceleration are actually a. one and the same concept, but expressed differently. b. b. rates of one another. c. entirely different concepts. d. expressions of distance traveled.

d) all of the above

Speed is a) a measure of how fast something is moving. b) always measured in terms or a unit or distance divided by a unit or time. c) the distance covered per unit time. d) all of the above. e) none of the above

a=6m/s^2 vi=0 t=1 we are looking for how far the car travelled so we will use (xf-xi= vi + 1/2 x a x t^2) xf-xi = 0 + 1/2 x 6 x 1^2 xf-xi = 3m

Starting from rest, a car undergoes a constant acceleration of 6 m/s How far will the car travel in the first second?

a. 5 km/h.s

Suppose a car is moving in a straight line and steadily increases its speed. It moves from 35 km/h to 40 km/h the first second and from 40 km/h to 45 km/h the next second. What is the car's acceleration? a. 5 km/h.s b. 10km/h.s c. 35 km/h.s d. 40 km/h.s e.45 km/h.s

c. Your velocity is constant

Suppose you are in a car that is going around a curve. The speedometer reads a constant 30 miles per hour. Which of the following is NOT true? a. You and the car are accelerating. b. Your acceleration is constantly changing. c. Your velocity is constant d. Your direction is constantly changing e. Your speed is constant.

b. 60 km/h. (speed=distance/time -> 180/3 = 60)

Suppose you take a trip that covers 180 km and takes 3 hours to make. Your average speed is a. 30 km/h. b. 60 km/h. c. 180 km/h. d. 360 km/h. e. 540 km/h.

FALSE

T/F A unit of acceleration is meters per second.

FALSE

T/F A unit of velocity is the meter.

FALSE

T/F Average speed is defined as the time it takes for a trip divided by the distance.

TRUE

T/F Even though a car is slowing down, it is still accelerating, in the most general definition of acceleration

FALSE

T/F Speed and velocity are the same.

true

T/F The rate at which distance is covered is called speed.

TRUE

T/F The rate at which velocity changes with time is called acceleration.

TRUE

T/F Velocity is different from speed in that velocity is speed in a given direction.

TRUE

T/F Velocity is the speed in a given direction.

FALSE

T/F When a car rounds a corner at a constant speed, its acceleration is zero.

TRUE

T/F When we discuss the motion of something, its motion is described relative to something else.

true

T/F does the term acceleration apply to increases AND decreases in speed?

Speed

The ................is the distance traveled in the time interval.

time=? speed= 0.6 m/s distance= 443m time = distance / speed time = 443 / 0.6 time = 738.3 seconds

The Sears Tower in Chicago is 443 m tall. Joe wants to set the world's stair climbing record and runs all the way to the roof of the tower. If Joe's average upward speed is 0.60 m/s, how long will it take Joe to climb from street level to the roof of the Sears Tower?

because the direction keeps changing

The car on the circular track may have a constant speed but not a constant velocity. Why?

Average velocity

The change in position divided by the time it took to cause this change A. Linear displacement C. Average velocity B. Angular displacement D. Instantaneous velocity

t=25s distance =1.73 km speed = distance/time = 1730/25 = 69.2m/s (we multiplied 1.73km by 1000 to turn it into meters)

The peregrine falcon is the fastest of flying birds (and, as a matter of fact, is the fastest living creature). A falcon can fly 1.73 km downward in 25 s. What is the speed of a peregrine falcon?

vector quantity

The quantity that has specific direction as well as magnitude is called

Scallar quantity

The quantity that requires only magnitude for a description is called

velocity

The slope of a position-time graph equals average ...........

rise. / run

The slope of a straight line is equal to its .... over its .....

Same speed and different velocities

The speedometer of a car moving northward reads 60 km/h. It passes another car that travels southward at 60 km/h. Do both cars have the same speed? Do they have the same velocity?

C. 15m/s2

What is the acceleration of a body that its velocity changed about 30 m/s during 25? A. 60m/52 B. 30m/s2 C. 15m/s2 D. 5m/s2

100-0 / 10 = 100/10 = 10km/h.s

What is the acceleration of the car that goes from rest to 100 km/h in 10 S?

velocity

When we say a car moves at 80 km/h to the north, we are specified its

speed

When we say a car travels at 80 km/h, we are specified its

d) instantaneous speed

When you look at the speedometer in a moving car, you can see the car's.. a) average distance traveled. b) instantaneous acceleration. c) average speed. d) instantaneous speed. e) average acceleration.

E) 50 km/hr southwest

Which of the following is the best statement for a velocity? A) 60 miles per hour B) 30 meters per second C) 30 km at 45° north of east D) 40 km/hr E) 50 km/hr southwest

B)Displacement is a vector and distance is a scalar.

Which of the following statements is true? A) Displacement is a scalar and distance is a vector. B) Displacement is a vector and distance is a scalar. C) Both displacement and distance are vectors. D) Neither displacement nor distance are vectors. E) Displacement and distance are always equal.

b) 4 (use t= vf-vi / a to. solve for the time and this equation was derived from a=vf-vi / t ----> t=24-0/6 = 4)

a car moves from at rest with an acceleration of 6m/s^2 during how many seconds the car velocity reaches 24m/s? a) 3 b) 4 c) 12 d) 16

scaler

mass, length, time, area, distance are all ................... quantities

m/s^2

the SI unit of acceleration is

deceleration

the decrease in acceleration is called

acceleration = change of velocity / time interval (memorise plz)

the formula of acceleration is

acceleration

the rate at which velocity changes is

its negative velocity because the slope is negative (going downwards)

this means that the velocity is ............

its zero because there is no slope

this means that the velocity is ..............

its positive velocity because the slope is positive (going upwards)

this means the velocity is ...............

vector

weight, displacement, acceleration are all .................... quantities

position at 4 s: 40m time at 20m: 2s

what is the position at 4 seconds, and what is the time at 20m?

B. 25 m/s(use vf=vi+at---> vf=0+2.5 x 10 = 25)

À car moves from at rest with an acceleration of 2.5m/s?, what is the velocity of the car after 10s from moving? A. 0.25 m/s B. 25 m/s c. 5m/s D. 50 m/s