Answer:112.82 m/s
Explanation:
Given
range of arrow=68 m

as the arrow travels it acquire a vertical velocity 

-------1
Range is given by
R=ut
where u=initial velocity


substitute the value of t in eqn 1

--------2
and 

substitute it in 2


u=112.82 m/s
Answer:
(a) convex mirror
(b) virtual and magnified
(c) 23.3 cm
Explanation:
The having mirror is convex mirror.
distance of object, u = - 20 cm
magnification, m = 1.4
(a) As the image is magnified and virtual , so the mirror is convex in nature.
(b) The image is virtual and magnified.
(c) Let the distance of image is v.
Use the formula of magnification.

Use the mirror equation, let the focal length is f.

Radius of curvature, R = 2 f = 2 x 11.67 = 23.3 cm
Answer:
a) 37.8 W
b) 2 Nm
Explanation:
180 g = 0.18 kg
We can also convert 180 revolution per minute to standard angular velocity unit knowing that each revolution is 2π and 1 minute equals to 60 seconds
180 rpm = 180*2π/60 = 18.85 rad/s
We can use the heat specific equation to find the rate of heat exchange of the steel drill and block:

Since the entire mechanical work is used up in producing heat, we can conclude that the rate of work is also 37.8 J/s, or 37.8 W
The torque T required to drill can be calculated using the work equation



Explanation:
Dark Energy. Dark Energy is a hypothetical form of energy that exerts a negative, repulsive pressure, behaving like the opposite of gravity. It has been hypothesised to account for the observational properties of distant type Ia supernovae, which show the universe going through an accelerated period of expansion
Answer:

Explanation:
given,
F = 14.1 i + 0 j + 5.1 k
displacement = 6 m
Assuming block is moving in x- direction
we know,
dW = F dx


![W = F[x]_0^6](https://tex.z-dn.net/?f=W%20%3D%20F%5Bx%5D_0%5E6)


hence, work done by the force is equal to 