Great Comprehensive College (2014 Mock Exam)

The equation x=ut represents the distance x travelled by a body moving on a straight road with a constant speed. In this equation, x represents the distance, u represents the constant speed, and t represents the time taken to travel that distance. This equation is derived from the formula distance = speed × time, where the speed remains constant throughout the motion. Therefore, x=ut is the most appropriate equation to represent the distance travelled by a body with a constant speed.

Concept of Matter

Position, Distance, Displacement and Speed

Position, Distance, Displacement and Speed

Position, Distance, Displacement and Speed

When a body moves with a constant speed but has no acceleration, it means that its velocity is not changing. Since acceleration is the rate of change of velocity, a body with no acceleration implies that its velocity remains constant over time. In such a scenario, the body will continue to move in a straight line, as there are no forces acting on it to cause it to change direction. Therefore, the correct answer is that the body moves in a straight line.

When the loaded test-tube is slightly depressed and released, it will undergo translational motion. Translational motion refers to the movement of an object from one place to another without any rotation or spinning. In this case, the test-tube will move in a straight line up and down, without any circular or rotational motion.

When two objects collide, the law of conservation of momentum states that the total momentum before the collision is equal to the total momentum after the collision. In this case, the first ball has an initial momentum of (0.5 kg)(10 m/s) = 5 kg·m/s, while the second ball is at rest with an initial momentum of 0 kg·m/s. After the collision, the two balls move off together, so their final momentum is equal. Therefore, the final momentum is also 5 kg·m/s. Since the two balls have equal mass, their final common velocity can be calculated using the equation final momentum = (total mass)(final velocity). Solving for the final velocity gives us (5 kg·m/s) / (1 kg + 1 kg) = 2.5 m/s. Therefore, the common velocity of the two balls after the collision is 2.5 m/s, or 2.5 ms-1 when rounded to one decimal place.

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Concept of Matter

When a body is acted upon by a couple, it undergoes rotational motion. A couple is a system of forces that consists of two equal and opposite forces acting on a body, but not along the same line. This creates a turning effect or torque on the body, causing it to rotate around an axis. Therefore, the correct answer is rotational.

The speed of the car relative to the old truck can be calculated by subtracting the speed of the truck from the speed of the car. In this case, the car is moving with a speed of 4ms-1 and the truck is approaching with a speed of 20ms-1. Therefore, the relative speed of the car with respect to the old truck is 4ms-1 - 20ms-1 = -16ms-1. However, since speed is a scalar quantity and cannot be negative, the magnitude of the relative speed is taken, resulting in 16ms-1. Therefore, the correct answer is 2.0ms-1.

A pair of callipers is the most suitable instrument for making accurate measurements of the internal diameter of a test tube. Callipers have two arms, one of which can be adjusted to fit inside the test tube, allowing for precise measurements. A meter rule and a tape rule are not suitable for measuring small dimensions accurately. A micro-meter-screw-gauge is used for measuring very small dimensions with high precision, but it may not be necessary for measuring the internal diameter of a test tube.

Concept of Matter

When the ball hits the wall and rebounds with the same speed, it experiences a change in momentum. The impulse experienced by an object is equal to the change in momentum it undergoes. In this case, since the ball rebounds with the same speed, its initial momentum is equal in magnitude but opposite in direction to its final momentum. Therefore, the change in momentum is equal to the initial momentum. The initial momentum is given by the product of the mass and the initial velocity, which is (5.0 kg)(2 m/s) = 10.0 kgm/s. Hence, the impulse experienced by the ball is 10.0 kgm/s.