A 50 kg boy climbs up a 8 m rope in gymnasium in 10 sec. The average power developed by the boy is approximately
400 watts
500 watts
4000 watts
None of these
Correct Answer :
A. 400 watts
Related Questions
Two balls of masses 3 kg and 6 kg are moving with velocities of 4 m/sec and 1 m/sec respectively, towards each other along the line of their centers. After impact the 3 kg ball comes to rest. This can happen only if the coefficient of restitution between the balls is
2/3
1/5
3/5
1/3
A stone is thrown up a slope of inclination 60° to the horizontal. At what angle to the slope must the stone be thrown so as to land as far as possible from the point of projection?
15°
30°
45°
75°
The maximum pull in a cable, carrying a uniformly distributed load and supported at two ends which are at the same level, is at
Supports
Quarter span
Mid span
None of the above
A 50 kg boy climbs up a 8 m rope in gymnasium in 10 sec. The average power developed by the boy is approximately
400 watts
500 watts
4000 watts
None of these
If a body is acted upon by a number of coplanar non-concurrent forces, it may
Rotate about itself without moving
Move in any one direction
Move in any one direction rotating about itself
All the above
If a particle moves with a uniform angular velocity ω radians/sec along the circumference of a circle of radius r, the equation for the velocity of the particle, is
v = ω √(y² - r²)
y = ω √(y - r)
v = ω √(r² + y²)
v = ω √(r² - y²)
To avoid bending action at the base of a pier,
Suspension and anchor cables are kept at the same level
Suspension and anchor cables are fixed to pier top
Suspension cable and anchor cables are attached to a saddle mounted on rollers on top of the pier
None the these
A ball is dropped from a height of 2.25 m on a smooth floor and rises to a height of 1.00 m after the bounce. The coefficient of restitution between the ball and the floor is
0.33
0.44
0.57
0.67
The velocity of a moving body, is
A vector quantity
A scalar quantity
A scalar as well as a vector quantity
None of these
Coefficient of friction depends on
Nature of surfaces only
Area of contact only
Both (A) and (B)
None of the above
The intrinsic equation of catenary is
S = c tan ψ
y = c cosh x/c
y = c cosh ψ
y = c sinh ψ
From the circular plate of a diameter 6 cm is cut out a circular plate whose diameter is equal to radius of the plate. The C.G. of the remainder shifts from the original position through
0.25 cm
0.50 cm
0.75 cm
1.00 cm
The centre of gravity of a quadrant of a circle lies along its central radius at a distance of
0.2 R
0.4 R
0.3 R
0.6 R
Pick up the correct statement from the following:
If two equal and perfectly elastic smooth spheres impinge directly, they interchange their velocities
If a sphere impinges directly on an equal sphere which is at rest, then a fraction ½(1 - e2) the original kinetic energy is lost by the impact
If two equal spheres which are perfectly elastic impinge at right angles, their direction after impact will still be at right angles
All the above
The C.G. of a thin hollow cone of height h, above its base lies on the axis, at a height of
h/3
h/4
2h/3
3h/4
The angle of projection at which the horizontal range and maximum height of a projectile are equal to
36°
45°
56°
76°
The motion of a bicycle wheel is
Translatory
Rotary
Rotary and translatory
Curvilinear
The unit of force in C.G.S. system of units, is called
Dyne
Newton
Kg
All the above
A simple pendulum of length l has an energy E, when its amplitude is A. If the length of pendulum is doubled, the energy will be
E
E/2
2E
4E
If three rigid rods are hinged together to form a triangle and are given rotary as well as translatory motion, the number of instantaneous centres of the triangle, will be
1
2
3
4
In the structure shown in below figure, the member which carries zero force, is 
AB
BC
BE
All the above
If the resultant of two forces P and Q acting at an angle θ makes an angle α with P, then tan α equals
P sin θ/P - Q cos θ
Q sin θ/P + Q cos θ
P sin θ/P + Q tan θ
Q sin θ/P + Q sin θ
On a mass m describing a circular path of radius r, the centrifugal force
Acts tangentially to the circular path
Acts towards the centre of rotation
Acts away from the centre of rotation
Is mw2r/g kgf
A uniform pyramid and a uniform prism of same height lie with their base on the surface. Which is more stable?
Pyramid
Prism
Both equally stable
None of the above
For a simple pendulum, the period of one oscillation is
2π √(l/2g)
2π √(2g/l)
2π √(l/g)
2π √(g/2l)
Power developed by a torque, is
2πNT kg m/min
2πNT/4500 h.p
2πNT /60 watts
All the above
The resultant of two forces acting at right angles is √34 kg and acting at 60° is 70 kg. The forces are
1 kg and 4 kg
2 kg and 3 kg
√3 kg and √5 kg
3 kg and 5 kg
The mechanical advantage of an ideal machine is 100. For moving the local through 2 m, the effort moves through
0.02 m
2 m
2.5 m
20 m
The numbers of funicular polygons which can be drawn to pass through two specified points in the space diagram are
Zero
1
2
Infinity
The centre of gravity of a trapezoidal dam section whose top width is a, bottom width is band the vertical side is a, from its vertical face is
(a² + ab + b²)/3 (a + b)
(b² + bc + c²)/3 (b + c)
(a² + ab + c²)/3 (a + c)
None of these