Physics Answers

 Two bodies A and B in figure are separated by a spring. Their motion down the incline is resisted by a force P = 800 N . The coefficient of kinetic friction is 0.30 under A and 0.10 under under B. a.) compute the acceleration of block A b.) Compute the acceleration of block B c.) Determine the force in the spring. *

 An elevator weighing 12 kN starts from rest and acquires an upward velocity of 2 m/sec in a distance of 5 m. If the acceleration is constant, what is the tension in the cable? *

An automobile starting from the rest speeds up to 15 m/sec. with a constant acceleration of 1.2 m/sec^2 , runs at fast speed for sometime and finally comes to the rest with the deceleration of 1.5 m/sec ^2 . If the total distance travelled is 400 m find the total time required. *

The acceleration of a point is a= 30t m/s^2. When t= 0, s=50 m, and V= 15 m/s. a.)What is the position of the point at t=3 sec? b.) What is the velocity of the point at t= 3 sec? c.) What is the acceleration of the point at t= 3 sec? *

 A feather is dropped on the moon from a height of 1.40 meters. The acceleration of gravity on the moon is 1.67 m/s^2. Determine the time for the feather to fall to the surface of the moon. *

A triode passes a plate current of 5mA at plate voltage 150V and grid voltage of -2V. If the grid voltage is changed to -35V, the plate current drops to 3.2mA but can be restored to 5mA by increasing plate voltage to 195V. Calculate

(1) mutual conductance

(2) a.c. plate resistance

(3) amplification factor

THE SPEED OF 5 KG BODY IS TO BE INCREASED FROM 10

M/S TO 20 M/S. WHAT CONSTANT FORCE IS NEEDED TO

PRODUCE THIS CHANGE IN SPEED IN EXACTLY 5 S ?

A rocket of mass 4×10⁴ kg, when full with fuel at launching pad, it's fired vertically upward and a burnout mass of 2×10⁴kg gases are exhausted at the rate of 20 slugs/second, with a velocity of 6×10³ m/s relative to the rocket (exhaust velocity) both quantities are assumed to be constant while the fuel is burning, what's the thrust, neglecting all external forces, what would be the speed of the rocket at burnout?

A car’s tachometer indicates the angular velocity of the engine’s crankshaft in rpm. A car stopped

at a traffic light has its engine idling at 500 rpm. When the light turns green, the crankshaft

rotation speeds up at a constant rate to 2500 rpm in a time interval of 3.0 s. How many

revolutions does the crankshaft make in these time interval?

. A 50 kg mass is sitting on a frictionless surface. An unknown constant force pushes the mass for

2 seconds until the mass reaches a velocity of 3 m/s

a. What is the initial momentum of the mass?

b. What is the final momentum of the mass?

c. What was the force acting on the mass?

d. What was the impulse acting on the mass?