QUARTER 3 SCIENCE 7
ACCELERATION (WEEK 3)
Objective: In this lesson, you will learn to describe the motion of an object in which velocity
changes in magnitude, direction, or both.
Activity 1- Speed or Velocity
Directions: Determine the following quantities whether it is speed or velocity. Write your answers
on your answer sheet.
Speed- the rate at which an object covers a distance. (example 10 meters per second)
Velocity- is the speed of an object and direction of motion. (example 60 kilometers to the North)
Table 1. Speed or Velocity
Measurements
1. 2 miles per hour
2. 15 meters per hour
3. 8 meters per second
4. 5 kilometers per hour
5. 50 meters per second
6. 3 miles per hour East
7. 15 meters per second
8. 15 meters per second Norths
9. 10 kilometers per hour West
10 kilometers per hour South
Speed or Velocity
Activity 2: Read Me!
Directions: The figure below shows the car’s speedometer reading with respect to time. Get the
speedometer’s reading of the car’s speed from 00:00 to 00:04 s. Write your answers on your answer
sheet.
Source: Science Third Quarter-Module 1 pp.15
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Vehicles rarely move at constant speed but oftentimes they changed speed. Consider the figure
below
Source: Science Third Quarter-Module 1 pp.16
The figure shows the speedometer’s readings of a car at 1 second interval within 4 seconds.
At time 00:00, the car is at rest. The car started to move at 00:01s with a speed of 5 km/h until at
00:04s the car’s speed is 50 km/h. The changing motion of an object is called acceleration.
Acceleration is defined as the rate of change in velocity.
The formula is,
Change in velocity is the difference between the final velocity (vf) and the initial velocity (vi).
Change in time is the difference between the final time (tf) and
the initial time (ti).
Average acceleration refers to the total change in velocity
divided by the total time taken for the change. Since the unit of
velocity is meter per second (m/s), acceleration is expressed in
meter per second per second (m/s/s). Oftentimes, the unit of
acceleration is written as m/s2.
Based on Figure 10, the car’s average acceleration is
Motion with constant acceleration is not common in everyday life, like a passenger vehicle
that moves along a highway. It can move at a constant velocity, changing velocity, or stop as it loads
and unloads passengers.
When a moving body decreases its velocity, it is said to decelerate. This negative acceleration
is called deceleration. Deceleration is the opposite of acceleration where the velocity of an object
decreases.
Example
A passenger vehicle with a speed of 20 m/s
slowed down to 10 m/s in 10 seconds.
What is its acceleration?
Solution:
Given: vi = 20 m/s
vf = 10 m/s
∆t = 10 s
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Activity 3: Solve Me!
Directions: Analyze and solve the problem below. Show your solution on your answer sheet
Problem: A racehorse coming out from the gate accelerates from rest to a velocity of 15
m/s West in 3 seconds. What is its acceleration?
Activity 4
Directions: Complete the paragraph by filling in the blanks using the correct word/s from the box.
Write your answers on your answer sheet.
Motion is a change in (1.) __________ with respect to a reference point. Distance and
displacement, speed and velocity, and acceleration are ways to describe motion. Distance is a (2.)
________
quantity having magnitude but no direction while (3.) __________ is a vector quantity
having both magnitude and direction. (4.) __________ speed refers to the total distance travelled
divided by the total time and (5.) __________ is displacement divided by total time of travel. A
(6.)__________ measures instantaneous speed/velocity. (7.) ________ motion refers to an object
moving with constant speed or constant velocity. (8.) __________ is defined as the change in velocity
in a time interval. Acceleration may change in any of the following conditions: when the velocity
changes, when the (9.) __________ of motion changes, or when both velocity and direction of motion
changes. (10.) __________ is the opposite of acceleration where the velocity of an object decreases.
Activity 5
Directions: Copy and complete the table by solving the missing values of the quantities. Write your
on your answer sheet.
Assessment:
Directions: Choose the letter of your answer and write your answers on your answer sheet.
1. The continuous change in position of an object with respect to a reference point.
A. At rest
C. Motion
B. Magnitude
D. Reference
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2. Rizalito was riding in a car how do Rizalito know when is an object considered to be in motion?
I.Position changes with respect to a point of reference
II.Distane changes with respect to a point of reference
III. Direction changes with respect to apoint of reference
IV. Speed changes with respect to a point of reference
A. I only
B. I and II only
C. I, II, and III
D. I, II and IV
3. Which of the following is TRUE about an object that travels 5 meters to the left, then 2 meters up,
then another 5 meters to the right?
A. Displacement of the object is equal to 12 meters.
B. Displacement of the object is equal to 12 meters down.
C. Total distance travelled by the object is equal to 12 meters.
D. Total distance travelled by the object is equal to 12 meters down.
4. The speed of an object at a specific moment in time is called________
A. Average Speed
C. Instantaneous Speed
B. Constant Speed
D. Zero Speed
5. Lydia runs 100 meters in 10 seconds, calculate her average speed?
A. 2 m/s
B. 5 m/s
C. 10 m/s
D. 20 m/s
6. A car traveling in a circle has changing velocity because it is_____.
A. not traveling at a constant speed
B. not traveling in a constant direction
C. traveling too slowly to measure its velocity
D. traveling in a constant direction at a constant speed
7. From home, Dong walked 300 m East to visit Inday. Both Dong and Inday walked another 400 m
North and 300 m West. Which of the following statements is NOT TRUE?
A. Dong went home.
B. Dong travelled a total distance of 1,000 m.
C. Dong’s displacement is zero if they continue to travel 400 m South.
D. Dong’s displacement is shorter than the total distance he has travelled.
8. Which of the following statements is TRUE?
A. I and II
B. II and III
C. I and III
D. I, II and III
9. This refers to the rate of change in velocity of an object.
A. Acceleration
C. Speed
B. Motion
D. Velocity
10. Two boys walked a 200-meter distance path. It takes 5 minutes for Boy
A to finish while 10 minutes for Boy B. Calculate and compare their speed?
A. Boy B is faster than Boy A
C. They have the same speed
B. Boy A is slower than Boy B
D. Boy A is twice faster than Boy B
Reference:
Science Third Quarter Module 1 – Describing Motion
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