Class 9 Physics TN State board
45 Marks / 90 Minutes
Measurement and Motion – Class 9 Question Paper
Section A: Multiple Choice Questions (1 mark each)
- What is the SI unit of length?
a) Kilogram
b) Meter
c) Second
d) Joule - If an object travels at a constant speed of 20 m/s for 4 seconds, what is the total distance covered?
a) 80 m
b) 40 m
c) 20 m
d) 10 m - Which of the following is a scalar quantity?
a) Velocity
b) Mass
c) Force
d) Acceleration - A car accelerates from 10 m/s to 30 m/s in 5 seconds. What is the acceleration of the car?
a) 2 m/s²
b) 4 m/s²
c) 6 m/s²
d) 8 m/s² - What is the formula for density?
a) Density = Mass/Volume
b) Density = Volume/Mass
c) Density = Force/Area
d) Density = Acceleration/Time
Section B: Short Answer Questions (3 marks each)
- Explain the difference between distance and displacement.
- A ball is thrown vertically upwards with an initial velocity of 15 m/s. Calculate the time it takes for the ball to reach its highest point. (Take g = 9.8 m/s²)
- Define the term “acceleration” and provide an example of an object undergoing positive acceleration.
- The length of a rectangular field is 40 m, and the width is 25 m. Calculate the area of the field.
- A car travels a distance of 120 km at a constant speed of 60 km/h. Calculate the time it takes for the journey.
Section C: Long Answer Questions (5 marks each)
- Derive the formula for average speed and explain its significance in motion.
- A stone is thrown horizontally from the top of a cliff with a velocity of 15 m/s. Calculate the time it takes for the stone to reach the ground. (Take g = 9.8 m/s²)
- Explain the concept of uniform motion and provide an example.
- A train accelerates from rest at a rate of 2 m/s². Calculate the distance it travels in the first 10 seconds.
- Discuss the importance of using standard units in measurements and provide examples.
Section A: Multiple Choice Questions (1 mark each)
b) Meter
a) 80 m
b) Mass
b) 4 m/s²
a) Density = Mass/Volume
Section B: Short Answer Questions (3 marks each)
Distance is the total path covered, while displacement is the change in position. Displacement is a vector quantity and includes both magnitude and direction.
Using the kinematic equation (v = u + gt), where (v) is final velocity, (u) is initial velocity, (g) is acceleration due to gravity, and (t) is time, we find (t = \frac{u}{g}). Substituting the values, (t = \frac{15}{9.8} \approx 1.53) seconds.
Acceleration is the rate of change of velocity with respect to time. Example: A car going from 0 to 60 km/h in 10 seconds.
Area = Length × Width = 40 m × 25 m = 1000 m².
Time = Distance/Speed = 120 km / 60 km/h = 2 hours.
Section C: Long Answer Questions (5 marks each)
Average Speed = Total Distance/Total Time. It gives the overall speed over the entire journey and is essential for analyzing and comparing motion.
The time it takes for the stone to reach the ground can be found using the equation (t = \sqrt{\frac{2h}{g}}), where (h) is the height and (g) is the acceleration due to gravity.
Uniform motion is when an object covers equal distances in equal intervals of time. Example: A car moving with a constant speed on a straight road.
Using the kinematic equation (s = ut + \frac{1}{2}at^2), where (s) is the distance, (u) is initial velocity, (a) is acceleration, and (t) is time, we find (s = 0 + \frac{1}{2}(2)(10)^2 = 100) meters.
Standard units ensure consistency and easy communication of measurements. For example, using the meter for length ensures that everyone understands the measurement in the same way, regardless of location.
These answers are meant to provide guidance, and it’s essential to check them against the specific context and curriculum you are using.