Physics Answers

A crate has a mass of 42 kg is placed on an 50° incline surface. The coefficient of friction between the crate and the surface is 0.85. If the crate is pushed down the incline at a rate of 2.25 m/s², determine:

a) the normal force 

b) the frictional force 

c) the pulling force P 

A string is 7.63 m long with a mass of 8.56 g. The string is held taut with a tension of 457 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?

A second year physical sciences student drives at an average speed of 40 km/h to see a friend, 

who lives a distance of 100km/h away (you may take the problem as being one-dimensional!). 

On arrival she discovers that he has misunderstood the arrangements and has already left to 

drive to visit her. She returns home, driving at an average speed of 70 km/h on the return trip. 

What is her average velocity for the whole journey? What is her average speed? If each left 

originally at the same time and his average speed is 30 km/h, who arrives first at her house? 

A simple pendulum complete one vibration in one sec. Find its length when = 10ms

What happens to the mass of water in a

pot when it cools, assuming no

molecules escape or are added? Is this

observable in practice? Explain.

Determine the effective capacitance if two capacitors, C1 = 10F and C2 = 5F, are

connected in parallel.

Determine the effective capacitance if two capacitors, C1 = 10F and C2 = 5F, are

connected in series.

How far must a 1.00x10-7C test charge (q) be from a 5.00x10-6C point

charge (Q) for it to experience a push of about 1.25 N?

An electric field with a strength of 1.25x104N/C exerted 2.50 N on a

certain test charge, q. Determine the charge on q.

Two objects with masses m1 and m2 are moving along the x-axis in the

positive direction with speeds v1 and v2, respectively, where v1 is less than

v2. The speed of the center of mass of this system of two bodies is

a) less than v1.

b) equal to v1.

c) equal to the average of v1 and v2.

d) greater than v1 and less than v2.

e) greater than v2.