Physics Mock Test- 4 - Class 9 MCQ

Independent variables are plotted along X-axis and Dependent variables are plotted along Y-axis. In the distance-time graph, time is independent and distance is a dependent variables.

60km.east + 90km.west =150km.

Non Uniform motion is defined as the motion of an object in which the object travels with varied speed and it does not cover same distance in equal time intervals, irrespective of the time interval length.

Examples:

1. If a car covers 10 meters in first two seconds, and 15 meters in next two seconds.

2. The motion of a train.

The correct option is A

is to note any change in the objects state of motion.

One way that you can recognize that a force is acting on an object is to note any change in the objects state of motion.

As given, W = 100 J, F = 15 N
We know, W = Fs 
⇒  s =  W/ F 
⇒  s =  100 / 15 
⇒  s =   6.6 m

According to the law of conservation of energy , energy can only be transformed from to form to another , it can neither be created nor destroyed . The total energy before and after the transformation always remains constant.

Speed of sound in air, v = 342 ms^-1

Time taken for hearing the echo, t = 3 s 

Distance  travelled by the sound = vt 

= 342 * 3 

= 1026 m

In 3 s, sound has to travel twice the distance between the the cliff and the person. 

Hence the distance between the cliff and the person is given by, d=  1730 m/2 = 865 m

Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied. It also determines the strength of its mutual gravitational attraction to other bodies. The basic SI unit of mass is the kilogram (kg).

The energy possessed by an oscillating pendulum of a clock is called mechanicalenergy. It is a combination of kinetic energy and potential energy. Kinetic energy is the one that is due to the motion of an object whereas potential energy due to the virtue of an objects position.

If no force is applied to a moving object, it should remain in motion as per the first law of motion. But, it is stopped due to friction.

The gravitational force for a falling object is along the direction of motion. Hence, its speed increases continuously till  it touches the ground.

F = m × a 
Where, F = force
m = mass
a = acceleration

Polar radius is 6357 km and equatorial radius is 6378 km. The shape of earth is not perfectly spherical. Poles are slightly closer to centre of earth. Weight of body at particular place is product of mass and acceleration due to gravity. So, weight and mass of body at particular position never be equal.

• When the ball moves upward, the force of gravitation is acting in the opposite direction of the ball that is why in that case acceleration is negative or in other words deceleration takes place.
• But when the ball is moving downwards the force of gravitation is in the same direction of the motion of the ball thus acceleration takes place in this case.

The motion of the particles of a medium when a sound wave is passing through it is oscillatory because the particles move forward set the neighbouring particle into motion and then come back to it's original position. The particles move to and fro which is also called oscillatory motion.

Correct Answer :- c

Explanation : An empty closed drum and a filled drum of same dimension will bring same upthrust and same volume

During reflection, sound waves obey the laws of reflections. To have an appreciable reflection of sound waves from any surface, it should have dimensions equal or larger than the wavelength of the sound waves failing on it. That us, a smaller object will not reflect the sound waves of larger wavelength.

Therefore, v² = 2 K.E. / m

Velocity with which missile strikes the ground = 143.2 m/s.

The child moves in the backward direction as a consequence of action-reaction law. Sandbag exerts an equal and opposite force in the backward direction.