Grade 9 Science Quiz

What is the unit of velocity?

• m

• m/s

• m/s2

• kg. m/s2

A sepak takraw ball is hit vertically upward by a player. What is its acceleration after 1 second?

• 1 m/s2

• 9.8 m/s2

• 0 m/s2

• -9.8 m/s2

A sipa is tossed vertically upward, with an initial velocity of 5 m/s and caught back at the same level as when it was thrown. What is the velocity of the ball at the point?

• -9.8 m/s2

• -9.8 m/s

• -5 m/s

• 0 m/s

Answer explanation

Since it reaches the same height, its velocity becomes 0 at the peak

A ball is thrown straight up. What's its speed at its highest height?

• 5 m/s

• 10 m/s

• 0 m/s

• 9.8 m/s

Answer explanation

a projectile momentarily stops on its maximum/highest point kaya 0 m/s

What is the formula of impulse?

• I = d/t

• I = ma

• I = mg

• I = Ft

What type of collision happens when the total kinetic energy of the system does not change and colliding objects bounce off after collision?

• Elastic Collision

• Inelastic Collision

• Vertical Collision

• Horizontal Collision

Answer explanation

So, an elastic collision is like a super bouncy high-five! All the energy from the movement stays in the system, just moving the objects in different directions. Here's the key:

• Elastic Collision: Think "bouncy fun!" All the energy stays in the system, making the objects bounce around.

• Inelastic Collision: Think "squishy splat!" Some energy is lost and not available for bouncing anymore.

Which of the following is an example of inelastic collision?

• billiards balls

• clay balls

• marble

• pingpong balls

Answer explanation

Imagine you have two balls made of different materials:

• bouncy ball (elastic): This ball is nice and firm, like a super bouncy ball.

• clay ball (inelastic): This ball is soft and squishy, like modeling clay.

• Elastic collision: Kinetic energy (energy of motion) is conserved, meaning most of the energy the object has before the collision is still there after, just in a different form (like bouncing).

• Inelastic collision: Kinetic energy is not conserved. Some of the energy is lost and converted into other forms, like heat, sound, or deformation of the objects.

In simpler terms:

• Elastic collision: Like a trampoline, bounces back with most of its energy.

• Inelastic collision: Like throwing playdough, loses energy and sticks or splats.

Calculate the momentum of a car, which has a mass of 1000 kg and moves with a velocity of 20 m/s.

• 500 kgm/s

• 10,020 kgm/s

• 20,000 kgm/s

• 99,980 kg m/s

What is referred to as an object that is acted solely upon by gravitational force?

• Project

• Projectile

• Target

• Trajectory

If you throw a baseball straight up, what is its vertical velocity at the highest point?

• 0 m/s

• 9.8 m/s

• 0 m/s2

• -9.8 m/s