Linear Motion and Forces

Question 1

What is a vector quantity?

Answer 1

vector quantity has both magnitude and direction.

Question 2

What is a scalar quantity

Answer 2

scalar quantity has a magnitude (value) only.

Question 3

What is acceleration?

Answer 3

the rate of change of velocity

Question 4

What is Newton’s first law

Answer 4

A body at rest will remain at rest, a body moving will continue to move at the same speed and direction unless acted upon by an unbalanced force.

Question 5

What is Newton’s second law

Answer 5

The acceleration of a body is directly proportional to the net force acting on the body and inversely proportional to its mass.

Question 6

What is Newton’s third law?

Answer 6

For every action force there is an equal and opposite reaction force.

Question 7

example of vector quantity

Answer 7

displacement, velocity, acceleration, force

Question 8

example of scalar quantity

Answer 8

distance, speed, time, mass

Question 9

what is distance

Answer 9

distance is the total length an object has moved- scalar quanity

Question 10

what is displacement

Answer 10

displacement is the distance an object has moved and the direction it’s moved from its original position- vector quantity.

Question 11

what is the average velocity of a boat that travels 400km north in a total of 8 hours. give your answer in km/hr and m/s

Answer 11

t= 8 hours s=400km
v=s/t
v= 400/8
v=50 km/hr

50/ 3.6
=13.89 m/s

Question 12

a jet is flying at a constant speed of 3400km/hr when the pilot blinks her eyes are closed for 100ms (0.1s) how far does the plane fly while her eyes are closed?

Answer 12

v= 3400km/hr
=3400/ 3.6
=944.4 m/s
t= o.1s
s=?

v=s/t
s=t x v
s=0.1 x 944.4
s= 94.44m

Question 13

a car is travelling at 20m/s when the driver applies breaks, it comes to a rest, with a deceleration of 7.5m/s/s. how long does it take for the car to stop

Answer 13

a= -7.5 m/s/s
vo=20 m/s
v=0
t=?
a= v-vo/ t
t=v-vo/a
t= 0-20/ -7.5
t= 2.67s

Question 14

a stone is thrown upwards at a speed of 20m/s.
A. how long will it take for the stone to reach its maximum height?

b. how high will it go

Answer 14

a. vo=20m/s
t=?
a= -9.8
v=o
a=v-vo/t
t=v-vo/a
t=0-20/-9.8
t=2.04s

B. s=vot + 1/2 at squared
s= 20x 2.04+1/2 (-9.8) x (2.04) squared
s=20.41m

Question 15

what does a straight line indicate on a distance time graph

Answer 15

constant speed
slope=speed

Question 16

what does an upwards curved line of a distance time graph indicate

Answer 16

the object is speeding up
slope at tangent = speed

Question 17

what does a straight line indicate on a velocity time graph

Answer 17

speed increased constantly– acceleration.

Question 18

what does a straight horizontal line indicate on a velocity time graph

Answer 18

constant speed
slope=0
acceleration= 0
area= base times height

Question 19

what two things can occur when an unbalanced force is exerted in an object

Answer 19

1. the motion of the object will change
2. the object is deformed in some way

Question 20

types of forces

Answer 20

frictional
elastic
tension
gravitational
electric
magnetic

Question 21

what equation is used to calculate average speed

Answer 21

v= distance/ time

Question 22

what is velocity

Answer 22

the speed in combination with the direction of an object.

Question 23

what is speed

Answer 23

how fast an object is moving

Question 24

how is average velocity calculated

Answer 24

displacement/time

Question 25

how is acceleration calculated

Answer 25

change in velocity/ time