# P2 Topic 3

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### An object will accelerate when

• A. The forces acting on it are balanced.
• B. The forces acting on it are unbalanced.
• C. Air resistance is equal to the object's weight
• D. Its weight is equal to the reaction from the ground.

### Jane compares the performance of some racing cars. She finds this information on the internet. Jane discovers that a racing car accelerates from 0 to 30 mph in 1.2 s. The speed of the car after 1.2 s from the start is about • A. 13 m/s
• B. 16 m/s
• C. 37 m/s
• D. 67 m/s

### A car is moving in a straight line. The graph shows the stopping of this car in an emergency. The resultant force on the car during the first second is • A. 0N
• B. 50/2N
• C. 50/1.5N
• D. 50N

### The acceleration of the car in the previous question whilst braking is

• A. -0.1 m/s2
• B. -9 m/s2
• C. -10 m/s2
• D. -12.5 m/s2

### On these graphs, the solid line shows the graph on page 12. Which graph shows what would happen if the car suddenly hit a small patch of oil on the road, just as the driver started to brake. • A.
• B.
• C.
• D.

### The diagram shows some forces acting on a car. The resultant of these forces is • A. 2000 N to the right.
• B. 3500 N to the right.
• C. 5500 N to the right.
• D. 7500 N to the right.

### The graph shows how the speeds of four identical cars change with time. Which line is for the car with the largest kinetic energy at time t? • A.
• B.
• C.
• D.

### A car accelerates at 2 m/s2. The mass of the car is 1000 kg. The force producing this acceleration is

• A. (2 / 1000) N
• B. (2 + 1000) N
• C. (1000 - 2) N
• D. (1000 x 2) N

### The diagram shows how the velocity of a falling object changes with time. At which point A, B, C or D is the resultant force on the object zero? • A.
• B.
• C.
• D.

• A.
• B.
• C.
• D.

### The mass of the engine is 100 000 kg and of each coach is 25 000 kg. When the train travels at constant speed, the engine still has to exert a force on coach Y. This is because • A. The coach has a large mass.
• B. The steam carries away thermal energy.
• C. There are frictional forces.
• D. Gravity always acts at right angles to the trains movement

• A. Zero
• B. 9 950 N
• C. 10 000 N
• D. 10 050 N

### As the train sets off, the resultant force on coach Y is 10 000 N. The acceleration produced by this force is

• A. 0.067 m/s²
• B. 0.4 m/s²
• C. 2.5 m/s²
• D. 15 m/s²

### The photograph shows a miniature train running on a level track. The engine driver applies the brakes on the engine. Which diagram shows the horizontal forces acting on the first coach? • A.
• B.
• C.
• D.