phy101 assignment no 2 Fall November 2011 solution

[Vuhelper]

View more random threads:

• Mgt301 Principles of Marketing VU Current Assignment No. 2...
• Fin621 Assignment No. 1 Spring April 2012
• Mgt402 Assignment No. 2 spring 2011
• ENG201 Assignment 2 Solution November 2011
• ISL201 Assignment No 1 Solution fall spring October 2011
• CS507 Information Systems Assignment 1 Spring 2011 Idea...
• Principles of Marketing MGT 301 assignment no 2 fall 2010
• Communication Skills- MCM301 assignment no 2 solution
• role and personality theory by Getzelz and Gauba
• ECO401 Assignment no 1 fall 2011 semester on 23 October,...

Question # 1 Marks = 12

A worker pushes 25Kg crate a distance of 5m along a level floor at constant velocity by pushing horizontally on it. The coefficient of kinetic frication between the crate and the floor is 0.23.

(a) What magnitude of force must the worker apply?

(b) How much work is done on the crate by this force?

(c) How much work is done on the crate by frication?

(d) How much work is done on the crate by normal force?

(e) How much work is done on the crate by the gravity?

(f) What is the total work done on the crate?

Sponsored Links



Question # 2 Marks = 8

The flywheel of a prototype car engine is under test. The angular position θ of the flywheel is given by θ = (3.0rad/s3)t3 and the diameter of the flywheel is 36cm.



(a)Find the distance that a particle on the rim moves during that time interval.

(b) Find the angle θ, in radians and in degree, at times t1 = 3.0s and t2 = 6.0s.

(c) Find the average angular velocity, in rad/s and in rev/min, between t1 = 3s and t2 = 6s.

(d) Find the instantaneous angular velocity at time t1 = 3.0s and t2 = 6.0s.

[Vuhelper]

Question No. 1:
A worker pushes 25kg crate a distance of 5m along a level floor at constant velocity by pushing horizontally on it. The coefficient of kinetic friction between the crate and the floor is 0.23.
a) What magnitude of force must the worker apply?
b) How much work is done on the crate by this force?
c) How much work is done on the crate by friction?
d) How much work is done on the crate by normal force?
e) How much work is done on the crate by the gravity?
f) What is the total work done on the crate?

Solution:
Mass = 25kg
Distance = 5m
Coefficient of friction =0.23N
W = mg
W = 25 × 9.8
W = 245 N
Fc = 245N
Fp =
Fp = 0N
Fv = 245cos 0
Fv = 245N
Ff = Fv
Ff =
Ff = 56.35 N

a) What magnitude of force must the worker apply?

Fap = Fp + Ff
Fap = 0 + 56.35
Fap = 56.35N

b) How much work is done on the crate by this force?

W = Applied Force × Distance
W = Fap × d
W = 56.35 × 5
W = 281.75 J

c) How much work is done on the crate by friction?

W = Force of Friction × Distance
W = Ff × d
W = 56.35 × 5
W = 281.75 J

d) How much work is done on the crate by normal force?

W = Fv × h
W = 245 × 0
W = 0 J

e) How much work done on the crate by the gravity?

W = Fc × h
W = 245 × 0
W = 0 J

f) What is the total work done on the crate?

W = 281.75 + 281.75 + 0 + 0
W = 563.5 J

Question No. 2:
The flywheel of a prototype car engine is under test. The angular position of the flywheel is given by = (3.0rad/s3)t3 and the diameter of the flywheel is 36 cm.

a) Find the distance that a particle on the rim moves during that time interval.
b) Find the angle , in radians and in degree, at times t1 = 3.0s and t2 = 6.0s.
c) Find the average angular velocity, in rad/s and in rev/min, between t1 = 3s and t2 = 6s
d) Find the instantaneous angular velocity at time t1 = 3.0s and t2 = 6.0s.

Solution:

a) Find the distance that a particle on the rim moves during that time interval.


Diameter = d = 36cm
= 3.0 rad/sec
Radius = r = 36/2
R = 18 cm
Distance = S =
S =
S = 54 cm
b) Find the angle , in radians and in degree, at times t1 = 3.0s and t2 = 6.0s.
Radian made in one second = 3 rad
Radian made at t1 = 3 × 3
= 9 rad
Radian made at t2 = 3 × 6
= 18 rad
c) Find the average angular velocity, in rad/s and in rev/min, between t1 = 3s and t2= 6s
Average velocity at t2 =


Average velocity at t1 =



d) Find the instantaneous angular velocity at time t1 = 3.0s and t2 = 6.0s.
Instantaneous angular velocity at t1

Instantaneous angular velocity at t2