CLASS VII- SCIENCE- WORKSHEET - 2 - FORCE AND MOTION- ANSWERS
WORKSHEET - 2
FORCE AND MOTION
I. Multiple choice questions
1. What is the unit of uniform velocity?
Ans: d. ms-1
2. Pallavan Express started from Chennai Egmore at 16:00 and reaches Karaikudi at 23:00. The distance covered by this train is 560 km. Calculate its velocity in kmph.
Ans:a. 80
3. A bowler bowled at a speed of 40 m/s. An Indian cricketer hits the ball, its moves in opposite direction with a speed of 60 m/s. What is the acceleration of the fall if time taken is 10 seconds?
Ans:c. 2m/s2
4. Find out the change in velocity of an object between 20s and 40s.
Ans:b. 4.5m/s
5. A boy riding a scooter covers a distance of 300m in 15s. What is the speed of the body?
Ans: c. 20m/s
6. An object is thrown upward, it experiences___________.
Ans: d. Non-uniform motion
7. If a body in motion covers equal distance in equal interval of time, then the body is said to be in uniform_______.
Ans: b. Speed
8. In a competition a sprinter starts from rest and achieves a velocity of 30m/s in a time of 6s. What is his average acceleration?
Ans: 5m/s
9. The basic unit of speed is_______.
Ans: d. m/s
10. Some of the students are interested to travel to a tourist spot Mamallapuram from Trichy. Which is about 350km far. They compute their average speed to be 50km/h. How many hours did the trip take?
Ans: b. 7km
11. The total length of a path taken by an object to travel from one place to the other is called______.
Ans: d. distance travelled
II. Fill in the blanks
12. If the velocity of an object decreases with time then the object is said to be in___________.
Ans: negative acceleration.
III. Answer briefly.
13. Complete the table
In the below table the speed of some organism is given. What is the distance covered by them in 100s?
Ans:
Time = 100s
Distance travelled = Speed X Time
14. A graph is drawn between distance and time. There are two cars A & B are with different acceleration. Which of the two is moving faster? Justify your answer.
Ans:
A is moving faster than B.
Gradient of A is also more than the gradient of B
15. A car starting from rest accelerates uniformly along a straight line. If it attains a velocity of 120kmph in 12s, what is the acceleration of the car in m/s2?
Given:
Velocity v= 120kmph
Time= 12s
Acceleration=?
a=v-u / t
Velocity is in kmph so we have to convert it into m/s
By converting v= 120km/h into m/s
We will get
=120 X 1000/36000
=33.33m/s
v=33.33m/s
u=0
a = v-u / t
= 33.33 - 0 / 12
= 2.77 m/s2
Acceleration of the car is 2.77 m/s2.