Mechanics | Relativity Answers

A basketball is dropped from a height of 2.0 m. Ignoring air resistance, what is the speed of the ball as it reaches the floor?

An unmarked police car traveling a constant 95km/h is passed by a speeder traveling 130km/h. Precisely 2.50s after the speeder passes, the police officer steps on the accelerator; if the police car's acceleration is 2.20m/s2 , how much time passes before the police car overtakes the speeder after the speeder passes (assumed moving at constant speed)?

What is the relation between force and momentum?

A boat that can move 3.0 m/s in still water is on a river that is flowing 1.0m/s (S) . What is the velocity of the boat relative to the shore when the boat is heading south?

19. When is the magnitude of the ball’s velocity equal to half its initial velocity?
a) 15.29 s & 45.87 s b) 3.06 s & 6.12 s c) 2.04 s & 3.06 s d) 0 s & 6.12 s
e) None of them

20. When is the magnitude of the ball’s displacement equal to half the maximum it rises?
a) 8.96 s & 52.20 s b) 0.90 s & 5.22 s c) 2.04 s & 3.06 s d) 3.06 s & 6.12 s
e) None of them

21. What are the magnitude and direction of the acceleration while the ball is
moving upward?
a) - 9.81 m/s2 upward b) - 9.81 m/s2 downward c) 9.81 m/s2 downward
d) 9.81 m/s2 upward e) None of them

22. What are the magnitude and direction of the acceleration while the ball is moving downward?
a) - 9.81 m/s2 upward b) - 9.81 m/s2 downward c) 9.81 m/s2 downward
d) 9.81 m/s2 upward e) None of them

23. What are the magnitude and direction of the acceleration when the ball is at the highest point?
a) - 9.81 m/s2 upward b) - 9.81 m/s2 downward c) 9.81 m/s2 downward
d) 9.81 m/s2 upward e) None of them

A frog jumps at an angle of 30o to the horizontal with an initial velocity of 36km/h.


24. The velocity vox of the frog is
a) 8.6 m/s b) 10.0 m/s c) 9.81 m/s d) -10.0 m/s e) None of them

25. The velocity voy of the frog is
a) 8.6 m/s b) 5.0 m/s c) 9.81 m/s d) -10.0 m/s e) None of them
26. The acceleration ax of the frog is
a) 9.81 m/s2 b) – 9.81 m/s2 c) 0.00 m/s2 d) 10.0 m/s2 e) None of them

27. The acceleration ay of the frog is
a) 9.81 m/s2 b) – 9.81 m/s2 c) 0.0 m/s2 d) 10.0 m/s2 e) None of them

9. The SI units of is
a) kgm-1s-1 b) kgms-1 c) ML-1T-1 d) No unit e) None of them

A motorist travelling 60 km/h brakes to a stop in 100 m.
10. Her acceleration assuming it to be constant, is
a) 1.39 m/s2 b) - 1.39 m/s2 c) 9.81 m/s2
d) - 9.81 m/s2 e) None of them

11. If her acceleration was a = - 9.81 m/s2, her stopping distance would be
a) 5.5 m b) 10.5 m c) 14.2 m d) 20.3 m e) None of them

12. Her stopping time in question 10 is
a) 20 s b) 30 s c) 15 s d) 12 s e) None of them

13. Her stopping time in question 11 is
a) 20 s b) 30 s c) 15 s d) 12 s e) None of them

A ball is thrown vertically upward from the ground with a velocity of 1.8 x 106cm/min.
14. The time it will take to reach its highest point will be
a) 30.58 s b) 10.20 s c) 3.06 s d) 0.31 s e) None of them

15. The maximum height reached by the ball will be
a) 9.81 m b) 0.46 m c) 4587.20 m d) 45.90 m e) None of them


16. How long after being thrown will the velocity of the ball be 10 m/s upward?
a) 2.04 s b) 29.60 s c) 10.20 s d) 2.96 s e) None of them

17. How long after being thrown will the velocity of the ball be 10 m/s downward?
a) 2.04 s b) 31.62 s c) 10.20 s d) 6.12 s e) None of them

18. When will the displacement of the ball be zero?
a) 0 s & 30.58 s b) 3.06 s & 6.12 s c) 2.04 s & 3.06 s d) 0 s & 61.16 s
e) None of them

1. Is it possible for two quantities to have the same dimensions but different units?
a) Yes b) No c) Yes only with Length d) Yes only with Time
e) Yes only with Mass

2. Is it possible for two quantities to have the same units but different dimensions?
a) Yes b) No c) Yes only with Length d) Yes only with Time
e) Yes only with Mass

3. One can always add two numbers that have the same units. Can one always add two numbers that have the same dimensions?
a) Yes b) No c) Yes only with Length d) Yes only with Time
e) Yes only with Mass

4. Which of the following equations are the units on the left side of the equals sign consistent with the units on the right side:
a) b) c) d)
e) None of them

Suppose we are told that the acceleration of a particle moving in a circle of radius r with uniform velocity v is proportional to some power of r according to the equation

where k is a dimensionless constant.

5. The value of n is
a) 0 b) 1 c) -1 d) 2 e) None of them

6. The value of m is
a) 0 b) 1 c) -1 d) 2 e) None of them

7. The equation of a in terms of the values of n and m
a)
b)
c)
d)
e) None of them

We're given an equation involving force, radius, length, speed, and distance, and are asked for the dimensions and SI units of eta ( ), which is viscosity.

8. The dimensions of is
a) b) c) ML-1T-1

You are driving on a highway at 20 m/s. Suddenly you see a deer step into the road, 110 m in front of you. Assume that your reaction time is 0.70 s and that your car brakes with constant accerleration.

A.)How far are you from the deer when you begin to apply the brakes?
B.)What accerleration will bring you to a rest right at the deer's posion.
C.) How long does it take you to stop?

(a) An object is subjected to three different forces, P, Q and R. The magnitude of each force is: P = 5 N, Q = 30 N, R = 10 N. P is a horizontal force acting eastward; Q acts at an angle 35 above the horizontal plane; and R is acting downward. Draw a diagram to show the forces acting on the object and calculate the resultant force acting on the object.

(b) Discuss an application of projectile motion by using an example. The mass, initial velocity and direction of the object must be described. Complete the discussion by deriving the equation to determine the location (x,y) of the object and drawing the path of the projectile motion on a graph paper.
Given the gravitational acceleration, g is 9.8 ms-2.

what is the effect on coefficient of static friction when side length of acube 5 cm is doubled to original?