Other Physics Answers

9. A car is driving down the road at 15 m/s when the driver notices a stop sign up ahead. The driver applies the brakes and comes to a stop in 5 seconds. What was the acceleration of the car when the brakes were applied?

10. A rock drop-off 1250 feet building, has height s (in feet) above the ground at time t seconds given by s (t) = 1250 - 16t2. What is the instantaneous velocity of the rock at 5 seconds?

11. A particle is in motion and is accelerating. The functional form of the velocity is v (t) = 20t - 5t2. Find the instantaneous acceleration at t = 3 seconds.

12. You are riding your bike downtown at a speed of 15 m/s and you see a red light ahead. You gently brake over a distance of 50 m and come to a complete stop. What is your acceleration during this time?

6. We want to design an airport runway with the following specifications. The lowest acceleration of a plane should be 4 m/s² and its take-off speed is 75 m/s. How long would the runway be to allow the planes to accelerate through it? 

7. An object moving with a slowing acceleration along a straight line. After 10s and covering a distance of 60m, its velocity reaches 4m/s. What is its initial velocity?

8. Suppose the position of a particle is given by s (t) = 1 + 3t - 2t², where t is in second and s is in meters.

a.    Find the displacement using the time interval between t = 1 and t = 3.

b.    Find the average velocity during the same time interval.

1. Renz is approaching a stoplight moving with a velocity of +30.0 m/s. The light turns yellow, and Renz applies the brakes and skids to a stop. If Renz acceleration is -8.00 m/s², then determine the displacement of the car during the skidding process.

2. A car slows down its motion from 10 m/s to 6 m/s in 2 seconds under constant acceleration. What is its acceleration?

3. A car starts its motion from rest and uniformly accelerates at a rate of 4 m/s² for 2 seconds in a straight line. How far did the car travel during those 2 seconds?

4. An object, without change in direction, travels a distance of 50 m with an initial speed of 5 m/s in 4 s. Find the object's velocity at the end of the given time interval? 

5. Ben Simmons is waiting at a stoplight. When it finally turns green, Ben accelerated from rest at a rate of 6.00 m/s² for a time of 4.10 seconds. Determine the displacement of Ben's car during this time period.

5. c) Find the total energy of a moving object of mass 6.3 kg and momentum 11.5*10^ 6 kgms^ -1 .

5. b) A matter has a body-centered cubic unit cell with a length of 330 pm along an edge and a density of 8.57 g cm^ -3 . Calculate the atomic mass of the matter.

4. c) If 12N force is applied to a fluid of cross-section 5.34 cm ^ 2 with a shearing rate of 0.7s ^ - 1 then find the viscosity of the fluid.

3. c) A wire of length 7 m and radius 2.37 mm is stretched by a load of 12370 gm and increased by 1.78% of the original length. Find the stress, strain, and Young's modulus of the material of the wire.

c) A capillary tube with an inside radius of 638 nm can support a 100 mm column of liquid that has a density of 820 kg * m ^ - 3 . The observed contact angle is 12.5 degrees . Find the surface tension of the liquid for h = 20 cm .

1. c) The radius of a silver bar is 30 cm. What force is required to stretch the bar by 12.7% of its length where Young's modulus is Y = 7.25 * 10 ^ 10 * N * m ^ - 2 .

A 700.0-N sign hangs from the end of a uniform strut. The strut is 4.0 m long and weighs

800.0 N. The strut is supported by a hinge at the wall and by a cable whose other end is tied

to the wall at a point 3.0 m above the left end of the strut. Find the tension in the supporting

cable and the force of the hinge on the strut.